perturb hits lock->lock_requests == LOCK_FREE_STATE assertion on Windows

_From [rnk@google.com](https://code.google.com/u/rnk@google.com/) on December 08, 2011 16:59:32_

Example build: http://build.chromium.org/p/client.drmemory/builders/win-7_x64-drm/builds/1772/ Assertion failure:
21: lock_requests ==
21: LOCK_FREE_STATE
21:
21: (Error occurred @3921 frags)
21:
21: version 3.0.1191, custom build
21:
21: -client_lib
21: 'E:\b\build\slave\win_7_x64_drm_checkout\build\build_drmemory-dbg-32/bin/debug/drmemorylib.dll;0;`-callstack_style`
21: `0x27` -no_results_to_stderr `-perturb_only` -logdir `E:\b\bui
21:
21: 0x21c3e808 0x6e5b1b4b
21:
21: 0x21c3e940 0x6e5b3b07
21:
21: 0x21c3e970 0x6e5324a7
21:
21: 0x21c3e988 0x6e532788
21:
21: 0x21c3e9a0 0x6e5326ad
21:
21: 0x21c3e9a8 0x6e4d113c
21:
21: 0x21c3e9b8 0x21bd8740
21:
21: 0x6e702f8e 0x8b5e5f01>

On Cygwin we get something a little different:
21: CMake Error at runtest.cmake:408 (message):
21: stderr failed to match "Starting", found "Starting" instead
21:
21: stderr:
21:
21: operable program or batch file.
21:
21:
21:
21:
21:
21:
21:
21:
21:
21: ~~Dr.M~~ To obtain results, run with: -results
21: E:/b/build/slave/win_7_x64_drm_checkout/build/build_drmemory-cyg-dbg-32/logs/DrMemory-winthreads.exe.1172.000
21:
21:
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21:

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=715_