[NCGenerics] SwiftSources == CompilerInvocation

Match up the additional flags in SwiftSources.cmake and
CompilerInvocation.cpp with respect to NoncopyableGenerics.

I think only CompilerInvocation is truly needed, though.

Author: kavon

lib/Frontend/CompilerInvocation.cpp

@@ -2654,6 +2654,9 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
   if (Args.hasArg(OPT_no_clang_module_breadcrumbs))
     Opts.DisableClangModuleSkeletonCUs = true;
 
+  if (SWIFT_ENABLE_EXPERIMENTAL_NONCOPYABLE_GENERICS)
+    Opts.DisableRoundTripDebugTypes = true; // temporary until we fix mangling!
+
   if (auto A = Args.getLastArg(OPT_enable_round_trip_debug_types,
                                OPT_disable_round_trip_debug_types)) {
     Opts.DisableRoundTripDebugTypes =