[parser] disallow language mode directive in body of function with non-simple parameters

src/scopes.cc

Index: src/scopes.cc
diff --git a/src/scopes.cc b/src/scopes.cc
index 9a6e3aae6da4d72b705970990826e3fd78308f90..61172513616d14db8fd26969cc4bd3e6bd858d9d 100644
--- a/src/scopes.cc
+++ b/src/scopes.cc
@@ -472,7 +472,6 @@ Variable* Scope::DeclareParameter(const AstRawString* name, VariableMode mode,
   Variable* var;
   if (mode == TEMPORARY) {
     var = NewTemporary(name);
-    has_simple_parameters_ = false;
   } else {
     var = variables_.Declare(this, name, mode, Variable::NORMAL,
                              kCreatedInitialized);
@@ -483,7 +482,6 @@ Variable* Scope::DeclareParameter(const AstRawString* name, VariableMode mode,
     DCHECK_NULL(rest_parameter_);
     rest_parameter_ = var;
     rest_index_ = num_parameters();
-    has_simple_parameters_ = false;
   }
   params_.Add(var, zone());
   return var;