Revert "[Flang] Allow compile *.f03, *.f08 file"

The test will fail in the MSVC environment.

This reverts commit 171794d.

Author: Shao-Ce SUN

clang/lib/Driver/Types.cpp

@@ -331,10 +331,6 @@ types::ID types::lookupTypeForExtension(llvm::StringRef Ext) {
       .Case("cui", TY_PP_CUDA)
       .Case("cxx", TY_CXX)
       .Case("CXX", TY_CXX)
-      .Case("F03", TY_Fortran)
-      .Case("f03", TY_PP_Fortran)
-      .Case("F08", TY_Fortran)
-      .Case("f08", TY_PP_Fortran)
       .Case("F90", TY_Fortran)
       .Case("f90", TY_PP_Fortran)
       .Case("F95", TY_Fortran)