[2/3] ntdll/tests: Use official path for temporary files instead of current directory.

[Marvin]

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=26707

Your paranoid android.


=== WXPX64 (64 bit file) ===
file.c:1008: Test failed: Invalid ioSb.Information: 3

=== WVISTAX64 (64 bit file) ===
file.c:1008: Test failed: Invalid ioSb.Information: 3

=== W7PROX64 (64 bit file) ===
file.c:1008: Test failed: Invalid ioSb.Information: 3

=== TEST64_W7SP1 (64 bit file) ===
file.c:1008: Test failed: Invalid ioSb.Information: 3