[CodeGen] Assert that EmittedDeferredDecls is empty

Its contents are transferred into DeferredDecls in Release(), so it
should be empty in moveLazyEmissionStates(). This matches the code
downstream in Cling.

Differential Revision: https://reviews.llvm.org/D156660

clang/lib/CodeGen/CodeGenModule.cpp

@@ -7455,6 +7455,8 @@ void CodeGenModule::moveLazyEmissionStates(CodeGenModule *NewBuilder) {
   assert(NewBuilder->DeferredDecls.empty() &&
          "Newly created module should not have deferred decls");
   NewBuilder->DeferredDecls = std::move(DeferredDecls);
+  assert(EmittedDeferredDecls.empty() &&
+         "Still have (unmerged) EmittedDeferredDecls deferred decls");
 
   assert(NewBuilder->DeferredVTables.empty() &&
          "Newly created module should not have deferred vtables");
@@ -7470,10 +7472,5 @@ void CodeGenModule::moveLazyEmissionStates(CodeGenModule *NewBuilder) {
 
   NewBuilder->TBAA = std::move(TBAA);
 
-  assert(NewBuilder->EmittedDeferredDecls.empty() &&
-         "Still have (unmerged) EmittedDeferredDecls deferred decls");
-
-  NewBuilder->EmittedDeferredDecls = std::move(EmittedDeferredDecls);
-
   NewBuilder->ABI->MangleCtx = std::move(ABI->MangleCtx);
 }