[MSVC] C:\gitP\facebook\folly\folly\test\MemsetBenchmark.cpp(38): error C3861: '__builtin_clzl': identifier not found

Error from MSVC, test "MemsetBenchmark.cpp" https://github.com/facebook/folly/blob/main/CMakeLists.txt#L1172 should be disabled on windows system.

```
C:\gitP\facebook\folly\folly\test\MemsetBenchmark.cpp(38): error C3861: '__builtin_clzl': identifier not found
C:\gitP\facebook\folly\folly\test\MemsetBenchmark.cpp(44): error C2065: '__asm__': undeclared identifier
C:\gitP\facebook\folly\folly\test\MemsetBenchmark.cpp(44): error C3878: syntax error: unexpected token 'volatile' following 'expression'
C:\gitP\facebook\folly\folly\test\MemsetBenchmark.cpp(44): error C2760: syntax error: ')' was unexpected here; expected ';'
C:\gitP\facebook\folly\folly\test\MemsetBenchmark.cpp(44): error C3878: syntax error: unexpected token ')' following 'expression-statement'
C:\gitP\facebook\folly\folly\test\MemsetBenchmark.cpp(89): error C3861: 'aligned_alloc': identifier not found
```

Start in CMakeLists.txt around line 1172 and inspect how MemsetBenchmark.cpp is registered. Reproduce or review the MSVC errors from folly/test/MemsetBenchmark.cpp, then confirm the benchmark is excluded on Windows and is still available on supported systems.

Written by the indexing model from the issue text.