Provide graceful handling of RegCreateKeyExW when lpSecurityAttributes->nLength is zero.
This reverts commit cc0716b65 (SVN r24491).
JIRA issue: CORE-15471
The code was trying to check whether the output string was already NULL terminated by RtlUnicodeToMultiByteN before NULL terminating it by checking DataStr[*count - 1] for a NULL terminator. But since RtlUnicodeToMultiByteSize always returns the size without the NULL terminator, DataStr[*count - 1] would always be the last actual character, never an optional NULL terminator.
For 0 sized strings this would actually lead to accessing the output buffer at position -1 (on 32 bit) or 0xFFFFFFFF (on 64 bit).
Fix this by removing the check. This fixes a crash in advapi32_winetest:registry on x64.
* [ADVAPI32] Simplify RtlCreateUnicodeStringFromAsciiz() return value check
RtlCreateUnicodeStringFromAsciiz() returns a BOOLEAN, not a BOOL.
No functional change.
Addendum to
CORE-14271
* [USER32] Simplify RtlCreateUnicodeStringFromAsciiz() return value check
RtlCreateUnicodeStringFromAsciiz() returns a BOOLEAN, not a UINT.
Also, add a FIXME.
No functional change.
Addendum to
CORE-14271
* [USER32] Simplify RegisterClipboardFormatA/W() a bit
No functional change.
* [UDFS] Simplify SeSinglePrivilegeCheck() return value check
No functional change.
Addendum to
CORE-14271
