Fix 3-way SSE4.2 crc32c usage in MSVC with CMake

Summary:
The introduction of the 3-way SSE4.2 optimized crc32c implementation in commit f54d7f5fea added the `HAVE_PCLMUL` definition when the compiler supports intrinsics for that instruction, but did not modify CMakeLists.txt to set that definition on MSVC when appropriate. As a result, 3-way SSE4.2 is not used in MSVC builds with CMake although it could be.

Since the existing test program in CMakeLists.txt for `HAVE_SSE42` already uses `_mm_clmulepi64_si128` which is a PCLMUL instruction, this PR sets `HAVE_PCLMUL` as well if that program builds successfully, fixing the problem.
Closes https://github.com/facebook/rocksdb/pull/3673

Differential Revision: D7473975

Pulled By: miasantreble

fbshipit-source-id: bc346b9eb38920e427aa1a253e6dd9811efa269e

CMakeLists.txt

@@ -229,6 +229,7 @@ int main() {
 unset(CMAKE_REQUIRED_FLAGS)
 if(HAVE_SSE42)
   add_definitions(-DHAVE_SSE42)
+  add_definitions(-DHAVE_PCLMUL)
 elseif(FORCE_SSE42)
   message(FATAL_ERROR "FORCE_SSE42=ON but unable to compile with SSE4.2 enabled")
 endif()