Tests: Skip old PrecompiledHeader test on IntelLLVM

This test uses hard-coded flags for a fixed set of compilers.
We have first-class PCH support implemented for IntelLLVM.

Tests/CMakeLists.txt

@@ -1948,7 +1948,7 @@ if(BUILD_TESTING)
     if(NOT CMAKE_C_COMPILER_ID STREQUAL "Clang" OR NOT "x${CMAKE_C_COMPILER_FRONTEND_VARIANT}" STREQUAL "xGNU")
       ADD_TEST_MACRO(ForceInclude foo)
     endif()
-    if(NOT CMAKE_C_COMPILER_ID STREQUAL "Clang")
+    if(NOT CMAKE_C_COMPILER_ID STREQUAL "Clang" AND NOT CMAKE_C_COMPILER_ID STREQUAL "IntelLLVM")
       ADD_TEST_MACRO(PrecompiledHeader foo)
     endif()
     set(MSVCRuntimeLibrary_BUILD_OPTIONS -DCMake_TEST_CUDA=${CMake_TEST_CUDA})