Disable some warnings for IntelLLVM on Windows.

Use /fp:precise to override IntelLLVM's default of /fp:fast.
This makes IsInf and IsNan work as expected by googletest.

```
[build]...\googletest\googlemock\test\gmock-function-mocker_test.cc(143,21): error: 'VoidReturning' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
[build]   MOCK_METHOD(void, VoidReturning, (int n));  // NOLINT
```

```
[build] ...\googletest\googlemock\test\gmock-function-mocker_test.cc(182,20): error: exception specification of overriding function is more lax than base version [-Werror,-Wmicrosoft-exception-spec]
[build]   MOCK_METHOD(int, CTNullary, (), (Calltype(STDMETHODCALLTYPE)));
```

```
[build] ...\googletest\googletest\test\googletest-death-test-test.cc(209,5): error: unused function 'DieInCRTDebugElse12' [-Werror,-Wunused-function]
[build] int DieInCRTDebugElse12(int* sideeffect) {
[build]     ^
```

```
[build] ...\googletest\googletest\test\gtest_unittest.cc(4096,7): error: variable 'n' set but not used [-Werror,-Wunused-but-set-variable]
[build]   int n = 0;
```

googletest/cmake/internal_utils.cmake

@@ -94,6 +94,9 @@ macro(config_compiler_and_linker)
     if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
       set(cxx_base_flags "${cxx_base_flags} -utf-8")
     endif()
+    if (CMAKE_CXX_COMPILER_ID STREQUAL "IntelLLVM")
+      set(cxx_base_flags "${cxx_base_flags} /fp:precise -Wno-inconsistent-missing-override -Wno-microsoft-exception-spec -Wno-unused-function -Wno-unused-but-set-variable")
+    endif()
   elseif (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR
       CMAKE_CXX_COMPILER_ID STREQUAL "IntelLLVM")
     set(cxx_base_flags "-Wall -Wshadow -Wconversion -Wundef")