Ensure code complete with !LoadExternal sees all local decls.

Summary:
noload_lookups() was too lazy: in addition to avoiding external decls, it
avoided populating the lazy lookup structure for internal decls.
This is the right behavior for the existing callsite in ASTDumper, but I think
it's not a very useful default, so we populate it by default.

While here:
 - remove an unused test file accidentally added in r322371.
 - remove lookups_begin()/lookups_end() in favor of lookups().begin(), which is
   more common and more efficient.

Reviewers: ilya-biryukov

Subscribers: cfe-commits, rsmith

Differential Revision: https://reviews.llvm.org/D42077

llvm-svn: 322548
diff --git a/clang/lib/Sema/SemaLookup.cpp b/clang/lib/Sema/SemaLookup.cpp
index c44a375..157d090 100644
--- a/clang/lib/Sema/SemaLookup.cpp
+++ b/clang/lib/Sema/SemaLookup.cpp
@@ -3543,7 +3543,8 @@
 
   // Enumerate all of the results in this context.
   for (DeclContextLookupResult R :
-       LoadExternal ? Ctx->lookups() : Ctx->noload_lookups()) {
+       LoadExternal ? Ctx->lookups()
+                    : Ctx->noload_lookups(/*PreserveInternalState=*/false)) {
     for (auto *D : R) {
       if (auto *ND = Result.getAcceptableDecl(D)) {
         Consumer.FoundDecl(ND, Visited.checkHidden(ND), Ctx, InBaseClass);