Reduce Windows build parallelism number (#9687)

Summary:
To avoid OOM issue for VS2007 build.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9687

Test Plan: Run VS2007 build 5 times, seems fine.

Reviewed By: ajkr

Differential Revision: D34845073

Pulled By: jay-zhuang

fbshipit-source-id: 60f84885e391e878ee6f3b1945376323baf47ec5

.circleci/config.yml

@@ -519,7 +519,7 @@ jobs:
             ${CMAKE_BIN} -G "${CMAKE_GENERATOR}" -DCMAKE_BUILD_TYPE=Debug -DOPTDBG=1 -DPORTABLE=1 -DSNAPPY=1 -DJNI=1 << parameters.extra_cmake_opt >> ..
             cd ..
             echo "Building with VS version: ${CMAKE_GENERATOR}"
-            msbuild.exe build/rocksdb.sln -maxCpuCount:64 -property:Configuration=Debug -property:Platform=x64
+            msbuild.exe build/rocksdb.sln -maxCpuCount -property:Configuration=Debug -property:Platform=x64
       - run:
           name: "Test RocksDB"
           shell: powershell.exe