ntdll: Use IsEqualGUID instead of memcmp to compare GUIDs.

[testbot at testbot.winehq.org]

Hi,

While running your changed tests on Windows, I think I found new failures.
Being a bot and all I'm not very good at pattern recognition, so I might be
wrong, but could you please double-check?
Full results can be found at
http://testbot.winehq.org/JobDetails.pl?Key=3928

Your paranoid android.


=== W2KPROSP4 (32 bit rtlstr) ===
rtlstr.c:1844: Test failed: Endianess broken

=== WXPPROSP3 (32 bit rtlstr) ===
rtlstr.c:1844: Test failed: Endianess broken

=== W2K3R2SESP2 (32 bit rtlstr) ===
rtlstr.c:1844: Test failed: Endianess broken

=== WVISTAADM (32 bit rtlstr) ===
rtlstr.c:1844: Test failed: Endianess broken

=== W2K8SE (32 bit rtlstr) ===
rtlstr.c:1844: Test failed: Endianess broken

=== W7PRO (32 bit rtlstr) ===
rtlstr.c:1844: Test failed: Endianess broken

=== W7PROX64 (32 bit rtlstr) ===
rtlstr.c:1844: Test failed: Endianess broken

=== W7PROX64 (64 bit rtlstr) ===
rtlstr.c:1844: Test failed: Endianess broken