Tests: Fix Module.WriteCompilerDetectionHeader for Intel on Windows

Fix a condition added by commit 091afa7342 (Tests: Teach tests when to
treat clang-cl as MSVC, 2018-11-06) to be specific to Clang.

Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt

@@ -128,7 +128,8 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU"
 endif()
 
 # for msvc the compiler version determines which c++11 features are available.
-if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC" OR "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC")
+if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC"
+    OR (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND "x${CMAKE_CXX_SIMULATE_ID}" STREQUAL "xMSVC"))
   if(";${CMAKE_CXX_COMPILE_FEATURES};" MATCHES ";cxx_delegating_constructors;")
     list(APPEND true_defs EXPECTED_COMPILER_CXX_DELEGATING_CONSTRUCTORS)
     list(APPEND true_defs EXPECTED_COMPILER_CXX_VARIADIC_TEMPLATES)