Remove the FIXME.

Author: vinivendra

lib/FrontendTool/FrontendTool.cpp

@@ -893,10 +893,6 @@ static SourceFile *getPrimaryOrMainSourceFile(CompilerInvocation &Invocation,
 /// files were specified, use them; otherwise, dump the AST to stdout.
 static void dumpAST(CompilerInvocation &Invocation,
                     CompilerInstance &Instance) {
-  // FIXME: WMO doesn't use the notion of primary files, so this doesn't do the
-  // right thing. Perhaps it'd be best to ignore WMO when dumping the AST, just
-  // like WMO ignores `-incremental`.
-
   auto primaryFiles = Instance.getPrimarySourceFiles();
   if (!primaryFiles.empty()) {
     for (SourceFile *sourceFile: primaryFiles) {