[lldb][NFCI] Remove unneeded use of ConstString in ASTResultSynthesizer

[bulbazord]

Summary

2/3 of the ConstStrings in this class were just to be able to log
something. Putting something in the StringPool just to log it doesn't
make a lot of sense, so let's remove them.

The remaining use is for RegisterPersistentDecl which is fine for now.

[bulbazord]

Remove unneeded newline from log line

lldb/source/Plugins/ExpressionParser/Clang/ASTResultSynthesizer.cpp

void ASTResultSynthesizer::RecordPersistentTypes(DeclContext *FunDeclCtx) {
   }
 }
 
 void ASTResultSynthesizer::MaybeRecordPersistentType(TypeDecl *D) {
   if (!D->getIdentifier())
     return;
 
   StringRef name = D->getName();
-
-  if (name.size() == 0 || name[0] != '$')
+  if (name.empty() || name.front() != '$')
     return;
 
-  Log *log = GetLog(LLDBLog::Expressions);
-
-  ConstString name_cs(name.str().c_str());
-
-  LLDB_LOGF(log, "Recording persistent type %s\n", name_cs.GetCString());
+  LLDB_LOG(GetLog(LLDBLog::Expressions), "Recording persistent type {0}", name);
 
   m_decls.push_back(D);
 }
 
 void ASTResultSynthesizer::RecordPersistentDecl(NamedDecl *D) {
   lldbassert(m_top_level);
 
   if (!D->getIdentifier())
     return;
 
   StringRef name = D->getName();
-
-  if (name.size() == 0)
+  if (name.empty())
     return;
 
-  Log *log = GetLog(LLDBLog::Expressions);
-
-  ConstString name_cs(name.str().c_str());
-
-  LLDB_LOGF(log, "Recording persistent decl %s\n", name_cs.GetCString());
+  LLDB_LOG(GetLog(LLDBLog::Expressions), "Recording persistent decl {0}", name);
 
   m_decls.push_back(D);
 }
 
 void ASTResultSynthesizer::CommitPersistentDecls() {
   auto *state =
       m_target.GetPersistentExpressionStateForLanguage(lldb::eLanguageTypeC);
   if (!state)
     return;
 
   auto *persistent_vars = llvm::cast<ClangPersistentVariables>(state);
 
   lldb::TypeSystemClangSP scratch_ts_sp = ScratchTypeSystemClang::GetForTarget(
       m_target, m_ast_context->getLangOpts());
 
   for (clang::NamedDecl *decl : m_decls) {
     StringRef name = decl->getName();
-    ConstString name_cs(name.str().c_str());
 
     Decl *D_scratch = persistent_vars->GetClangASTImporter()->DeportDecl(
         &scratch_ts_sp->getASTContext(), decl);
 
     if (!D_scratch) {
       Log *log = GetLog(LLDBLog::Expressions);
 
       if (log) {
         std::string s;
         llvm::raw_string_ostream ss(s);
         decl->dump(ss);
         ss.flush();
 
         LLDB_LOGF(log, "Couldn't commit persistent  decl: %s\n", s.c_str());
       }
 
       continue;
     }
 
     if (NamedDecl *NamedDecl_scratch = dyn_cast<NamedDecl>(D_scratch))
-      persistent_vars->RegisterPersistentDecl(name_cs, NamedDecl_scratch,
-                                              scratch_ts_sp);
+      persistent_vars->RegisterPersistentDecl(ConstString(name),
+                                              NamedDecl_scratch, scratch_ts_sp);
   }
 }
 
 void ASTResultSynthesizer::HandleTagDeclDefinition(TagDecl *D) {
   if (m_passthrough)
     m_passthrough->HandleTagDeclDefinition(D);
 }