Fix access to type variables in initializer expressions

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
===================================================================
--- runtime/vm/parser.cc	(revision 25809)
+++ runtime/vm/parser.cc	(working copy)
@@ -5057,16 +5057,11 @@
 
 void Parser::CaptureInstantiator() {
   ASSERT(current_block_->scope->function_level() > 0);
-  const bool kTestOnly = false;
-  // Side effect of lookup captures the instantiator variable.
-  LocalVariable* instantiator = NULL;
   if (current_function().IsInFactoryScope()) {
-    instantiator = LookupTypeArgumentsParameter(current_block_->scope,
-                                                kTestOnly);
+    current_block_->scope->CaptureVariable(Symbols::TypeArgumentsParameter());
   } else {
-    instantiator = LookupReceiver(current_block_->scope, kTestOnly);
+    current_block_->scope->CaptureVariable(Symbols::This());
   }
-  ASSERT(instantiator != NULL);
 }