[PATCH] d3dcompiler: Add an assert checking for writemask sanity in debug_writemask().

[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:
https://testbot.winehq.org/JobDetails.pl?Key=45445

Your paranoid android.


=== debian9 (build log) ===

error: patch failed: dlls/d3dcompiler_43/utils.c:2142
Task: Patch failed to apply

=== debian9 (build log) ===

error: patch failed: dlls/d3dcompiler_43/utils.c:2142
Task: Patch failed to apply