[Driver] Remove Flags from cl_Group. NFC

These flags are redundant since everything in the `cl_Group`
explicitly sets flags anyway. Remove the Flags because they're
confusing and will cause problems with some later refactorings.

Author: bogner

clang/include/clang/Driver/Options.td

@@ -6883,7 +6883,7 @@ def defsym : Separate<["-"], "defsym">,
 // clang-cl Options
 //===----------------------------------------------------------------------===//
 
-def cl_Group : OptionGroup<"<clang-cl options>">, Flags<[CLDXCOption]>,
+def cl_Group : OptionGroup<"<clang-cl options>">,
   HelpText<"CL.EXE COMPATIBILITY OPTIONS">;
 
 def cl_compile_Group : OptionGroup<"<clang-cl compile-only options>">,