Remove --harmony-modules flag and let embedder decide when modules are used

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index dc67e536c8e0eb76f9921bd712fa9fbc0ddb0e58..4ed8f12841cf4afc95f70e090b42f158ac3bc080 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -362,7 +362,6 @@ class ParserBase : public Traits {
 
   Scope* NewScope(Scope* parent, ScopeType scope_type, FunctionKind kind) {
     DCHECK(ast_value_factory());
-    DCHECK(scope_type != MODULE_SCOPE || FLAG_harmony_modules);
     Scope* result = new (zone())
         Scope(zone(), parent, scope_type, ast_value_factory(), kind);
     result->Initialize();