[MERGE #1659 @obastemur] Fix buffer overflow of a global variable
[MERGE #1659 @obastemur] Fix buffer overflow of a global variable

Merge pull request #1659 from obastemur:fix_global_heap

`memcmp` was reaching beyond the global variable ~~heap~~ buffer.

`cch` does not include `sizeof(char16)` while `pszs->cch` includes that. See https://github.com/Microsoft/ChakraCore/blob/master/lib/Runtime/Library/DateImplementation.cpp#L1199-L1200

Microsoft/ChakraCore,mrkmarron/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,Microsoft/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore,mrkmarron/ChakraCore