[Bug 3660] Off-by-one error in DOMString.cpp. And check that memory has been...

[Bug 3660] Off-by-one error in DOMString.cpp.  And check that memory has been acquired successfully after memory acquistion requests in DOMString.


git-svn-id: https://svn.apache.org/repos/asf/xerces/c/trunk@173151 13f79535-47bb-0310-9956-ffa450edef68