[XERCESC-2235] DFAContentModel::buildDFA(): correctly zero-initialize fFollowList

Due to a copy&paste issue, the intended zero-initialization of
fFollowList wasn't done (copy&paste issue), and thus in case of
OutOfMemory exception when initializing the array, the memory freeing in
cleanup() could access uninitialized elements.

Follow-up of https://github.com/apache/xerces-c/pull/40 / a65990d7

Fixes GDAL's https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=42636

[XERCESC-2230] DFAContentModel::buildSyntaxTree(): fix memory leaks when OutOfMemoryException occurs

Fixes GDAL's https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=40866

[XERCESC-2229] IGXMLScanner::scanDocTypeDecl(): fix memory leak on exception

The method can leak pubId and sysId when subsequent call to
fReaderMgr.skipPastSpaces() throws an exception (e.g. a
TranscodingException)

[XERCESC-2228] DFAContentModel: fix memory leaks when OutOfMemoryException occurs

[XERCESC-2227] Memleak fixes in ContentSpecNode and ComplexTypeInfo classes

XERCESC-2208: XMLSize_t size_t revert

ComplexTypeInfo::expandContentModel(): restore use of retNode as in original code (this is equivalent)

Fixes GDAL's https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=39159

XERCESC-2208: Use cstdint and standard integer types

XERCESC-2226: Update minimum CMake version to 3.12

* Required for CURL imported target usage in XERCESC-2225
* Drop old cmake_policy settings which are now the default behaviour

XERCESC-2225: Link to installed CMake targets of CURL

[XERCESC-2224] DFAContentModel::checkUniqueParticleAttribution (): speed enhancement

The complexity of this method is roughly O(n^3). Fuzzers can generate
schemas with n = several thousands. The test fTransTable[i][j] == XMLContentModel::gInvalidTrans
is independant of the k loop, and can thus being moved at a upper level
to improve runtime.

[XERCESC-2223] SAX2XMLReaderImpl::error(): use exception memory manager, …

SAX2XMLReaderImpl::error(): use exception memory manager, otherwise regular memory manager might fail to fully allocate the strings in the exception and cause memory leaks

[XERCESC-2222] DFAContentModel::checkUniqueParticleAttribution(): fix memory leak

If a memory allocation of conflictTable[] fails, or later in the
function, the array is not freed.
Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=38533

Fix -Wmemset-transposed-args warnings of clang++

XERCESC-2221: InMemMsgLoader::loadMsg(): fix memory leak when transcoding fails.

Just like how it was done for ICU

Fixes:
xercesc/util/XMLChTranscoder.cpp:73:23: warning: setting buffer to a 'sizeof' expression; did you mean to transpose the last two arguments? [-Wmemset-transposed-args]
    memset(charSizes, sizeof(XMLCh), countToDo);
                      ^
xercesc/util/XMLChTranscoder.cpp:73:23: note: cast the second argument to 'int' to silence

and

xercesc/util/XMLUTF16Transcoder.cpp:114:23: warning: setting buffer to a 'sizeof' expression; did you mean to transpose the last two arguments? [-Wmemset-transposed-args]
    memset(charSizes, sizeof(UTF16Ch), countToDo);
                      ^
xercesc/util/XMLUTF16Transcoder.cpp:114:23: note: cast the second argument to 'int' to silence
1 warning generated.

Seen with the IconvGNU transcoder when parsing "<aaa.xsdopengis.net/gml\x96".
The reason is that XMLString::transcode(repText2, manager) throws a TranscodingException
which causes the tmp1 string to leak.

```
0 0x8791409 in operator new(unsigned int) /src/llvm-project/compiler-rt/lib/asan/asan_new_delete.cpp:99:3
1 0xbd147f7 in xercesc_4_0::MemoryManagerImpl::allocate(unsigned int) gdal/xerces-c/src/xercesc/internal/MemoryManagerImpl.cpp:40:18
2 0xbe8c73e in xercesc_4_0::IconvGNULCPTranscoder::transcode(char const*, xercesc_4_0::MemoryManager*) gdal/xerces-c/src/xercesc/util/Transcoders/IconvGNU/IconvGNUTransService.cpp:870:32
3 0xbc22ca2 in xercesc_4_0::XMLString::transcode(char const*, xercesc_4_0::MemoryManager*) gdal/xerces-c/src/xercesc/util/XMLString.cpp:621:25
4 0xbe8f4ad in xercesc_4_0::InMemMsgLoader::loadMsg(unsigned int, char16_t*, unsigned int, char const*, char const*, char const*, char const*, xercesc_4_0::MemoryManager*) gdal/xerces-c/src/xercesc/util/MsgLoaders/InMemory/InMemMsgLoader.cpp:157:16
5 0xbc20175 in xercesc_4_0::XMLException::loadExceptText(xercesc_4_0::XMLExcepts::Codes, char const*, char const*, char const*, char const*) gdal/xerces-c/src/xercesc/util/XMLException.cpp:241:23
6 0xbc48bee in xercesc_4_0::UTFDataFormatException::UTFDataFormatException(char const*, unsigned long long, xercesc_4_0::XMLExcepts::Codes, char const*, char const*, char const*, char const*, xercesc_4_0::MemoryManager*) gdal/xerces-c/src/xercesc/util/UTFDataFormatException.hpp:31:1
7 0xbc4824e in xercesc_4_0::XMLUTF8Transcoder::transcodeFrom(unsigned char const*, unsigned int, char16_t*, unsigned int, unsigned int&, unsigned char*) gdal/xerces-c/src/xercesc/util/XMLUTF8Transcoder.cpp:182:13
8 0xbd27d7e in xercesc_4_0::XMLReader::xcodeMoreChars(char16_t*, unsigned char*, unsigned int) gdal/xerces-c/src/xercesc/internal/XMLReader.cpp:1926:34
9 0xbd271dd in xercesc_4_0::XMLReader::refreshCharBuffer() gdal/xerces-c/src/xercesc/internal/XMLReader.cpp:571:19
10 0xbd15c63 in xercesc_4_0::XMLReader::peekNextChar(char16_t&) gdal/xerces-c/src/xercesc/internal/XMLReader.hpp:767:14
11 0xbd15aaf in xercesc_4_0::ReaderMgr::peekNextChar() gdal/xerces-c/src/xercesc/internal/ReaderMgr.cpp:158:21
12 0xbd328da in xercesc_4_0::XMLScanner::scanProlog() gdal/xerces-c/src/xercesc/internal/XMLScanner.cpp:1241:45
13 0xbd31ef4 in xercesc_4_0::XMLScanner::scanFirst(xercesc_4_0::InputSource const&, xercesc_4_0::XMLPScanToken&) gdal/xerces-c/src/xercesc/internal/XMLScanner.cpp:549:9
14 0xbdadcff in xercesc_4_0::SAX2XMLReaderImpl::parseFirst(xercesc_4_0::InputSource const&, xercesc_4_0::XMLPScanToken&) gdal/xerces-c/src/xercesc/parsers/SAX2XMLReaderImpl.cpp:500:22
```

XERCESC-2219: XMLReader constructor: fix memory leak when refreshRawBuffer() throws

XERCESC-2218: CurlURLInputStream constructor: avoid memory leak

XERCESC-2217: ICUTranscoder::transcodeFrom(): fix read heap-buffer-overflow