non-det uninit in ntdll!RtlpLowFragHeapAllocFromContext in tsan tests

_From [bruen...@google.com](https://code.google.com/u/109494838902877177630/) on July 02, 2012 09:09:48_

showed up on bot: http://build.chromium.org/p/client.drmemory/builders/win-7_x64-drm/builds/2272/steps/dbg%20full%20nosyms%20TSan%20tests/logs/stdio callstack 2nd frame looks wrong which is annoying, after all my callstack work:

~~Dr.M~~
~~Dr.M~~ Error `#1`: UNINITIALIZED READ: reading register eax
~~Dr.M~~ # 0 ntdll.dll!LdrUnlockLoaderLock +0xf0 (0x77a06d4c )
~~Dr.M~~ # 1 MSCTF.dll!CtfImeCreateInputContext +0x226e (0x7702e559 )
~~Dr.M~~ # 2 ntdll.dll!RtlAllocateHeap +0xab (0x779fe0f2 )
~~Dr.M~~ # 3 _heap_alloc_base [f:\dd\vctools\crt_bld\self_x86\crt\src\malloc.c:105]
~~Dr.M~~ # 4 _heap_alloc_dbg_impl [f:\dd\vctools\crt_bld\self_x86\crt\src\dbgheap.c:427]
~~Dr.M~~ # 5 _nh_malloc_dbg_impl [f:\dd\vctools\crt_bld\self_x86\crt\src\dbgheap.c:239]
~~Dr.M~~ # 6 _nh_malloc_dbg [f:\dd\vctools\crt_bld\self_x86\crt\src\dbgheap.c:296]
~~Dr.M~~ # 7 malloc [f:\dd\vctools\crt_bld\self_x86\crt\src\dbgmalloc.c:56]
~~Dr.M~~ # 8 operator new [f:\dd\vctools\crt_bld\self_x86\crt\src\new.cpp:59]
~~Dr.M~~ # 9 testing::internal::MakeAndRegisterTestInfo [e:\b\build\slave\win_7_x64_drm_checkout\tsan\third_party\googletest\src\gtest.cc:2157]
~~Dr.M~~ `#10` `dynamic initializer for 'PositiveTests_RaceInMemcpy::PositiveTests_RaceInStrncmp_Test::test_info_'' [e:\b\build\slave\win_7_x64_drm_checkout\tsan\unittest\racecheck_unittest.cc:6622]
~~Dr.M~~ `#11` _cinit [f:\dd\vctools\crt_bld\self_x86\crt\src\crt0dat.c:307]
~~Dr.M~~ Note: @0:00:05.188 in thread 4084
~~Dr.M~~ Note: instruction: cmp %eax %ecx

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=933_