[clang-tidy] Avoid expensive AST traversal in RedundantTypenameCheck

In Fuchsia, we have several files that take over 2 hours for this check
to run, where as it only takes 8 seconds to finish without the
RedundantTypenameCheck.  We can avoid this exponential behavior by
limiting the use of hasAncestor to typeLocs for the types that are
actually used in the checking logic.

From the wall time for the check with --enable-profile goes from 6724
seconds (about 2 hours) to down to a reasonable 0.1753 seconds.

Author: ilovepi

clang-tools-extra/clang-tidy/readability/RedundantTypenameCheck.cpp

@@ -18,9 +18,13 @@ using namespace clang::ast_matchers;
 namespace clang::tidy::readability {
 
 void RedundantTypenameCheck::registerMatchers(MatchFinder *Finder) {
-  Finder->addMatcher(typeLoc(unless(hasAncestor(decl(isInstantiated()))))
-                         .bind("nonDependentTypeLoc"),
-                     this);
+  Finder->addMatcher(
+      typeLoc(loc(TypeMatcher(anyOf(typedefType(), tagType(),
+                                    deducedTemplateSpecializationType(),
+                                    templateSpecializationType()))),
+              unless(hasAncestor(decl(isInstantiated()))))
+          .bind("nonDependentTypeLoc"),
+      this);
 
   if (!getLangOpts().CPlusPlus20)
     return;