[compiler-rt] Fix Sanitizer-common Unittests on win64

Summary:
This patch is fixing unittests that are broken on windows (64-bits).

Tests under 'SANITIZER_CAN_USE_ALLOCATOR64' are disabled.
A custom allocator for windows based on WinHeap API will replace these tests.

Tested on Win32/Win64 (Ninja and MSVC).
Tested on Linux 32-bit/64-bit clang.

```
C:\src\llvm\build64\projects\compiler-rt>lib\sanitizer_common\tests\Release\Sanitizer-x86_64-Test.exe
[==========] Running 101 tests from 12 test cases.
[----------] Global test environment set-up.
[----------] 51 tests from SanitizerCommon
[ RUN      ] SanitizerCommon.DefaultSizeClassMap
[       OK ] SanitizerCommon.DefaultSizeClassMap (1 ms)
[ RUN      ] SanitizerCommon.CompactSizeClassMap
[       OK ] SanitizerCommon.CompactSizeClassMap (1 ms)
[ RUN      ] SanitizerCommon.InternalSizeClassMap
[       OK ] SanitizerCommon.InternalSizeClassMap (1 ms)
[ RUN      ] SanitizerCommon.SizeClassAllocator32Compact
[       OK ] SanitizerCommon.SizeClassAllocator32Compact (828 ms)
[ RUN      ] SanitizerCommon.SizeClassAllocator32CompactMetadataStress
[       OK ] SanitizerCommon.SizeClassAllocator32CompactMetadataStress (914 ms)
[ RUN      ] SanitizerCommon.SizeClassAllocator32MapUnmapCallback

[...]

[----------] 4 tests from Symbolizer
[ RUN      ] Symbolizer.ExtractToken
[       OK ] Symbolizer.ExtractToken (0 ms)
[ RUN      ] Symbolizer.ExtractInt
[       OK ] Symbolizer.ExtractInt (0 ms)
[ RUN      ] Symbolizer.ExtractUptr
[       OK ] Symbolizer.ExtractUptr (0 ms)
[ RUN      ] Symbolizer.ExtractTokenUpToDelimiter
[       OK ] Symbolizer.ExtractTokenUpToDelimiter (0 ms)
[----------] 4 tests from Symbolizer (24 ms total)

[----------] Global test environment tear-down
[==========] 101 tests from 12 test cases ran. (5090 ms total)
[  PASSED  ] 101 tests.
```

Reviewers: rnk

Subscribers: chrisha, wang0109, llvm-commits, kubabrecka

Differential Revision: http://reviews.llvm.org/D21817

llvm-svn: 274174