Improve async code in VM by not unnecessarily capturing parameters of async and

runtime/vm/flow_graph_builder.h

Index: runtime/vm/flow_graph_builder.h
diff --git a/runtime/vm/flow_graph_builder.h b/runtime/vm/flow_graph_builder.h
index 2211da403c3ec7016f797efa988ccad5577c6ea1..7070e2ae9b2cb25eda2ee346db7125d61f067f1a 100644
--- a/runtime/vm/flow_graph_builder.h
+++ b/runtime/vm/flow_graph_builder.h
@@ -164,7 +164,6 @@ class FlowGraphBuilder : public ValueObject {
 
   intptr_t next_await_counter() { return jump_count_++; }
 
-  ZoneGrowableArray<intptr_t>* await_levels() const { return await_levels_; }
   ZoneGrowableArray<JoinEntryInstr*>* await_joins() const {
     return await_joins_;
   }
@@ -254,7 +253,6 @@ class FlowGraphBuilder : public ValueObject {
 
   intptr_t jump_count_;
   ZoneGrowableArray<JoinEntryInstr*>* await_joins_;
-  ZoneGrowableArray<intptr_t>* await_levels_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(FlowGraphBuilder);
 };
@@ -465,18 +463,6 @@ class EffectGraphVisitor : public AstNodeVisitor {
 
   void BuildLetTempExpressions(LetNode* node);
 
-  void BuildSyncYieldJump(LocalVariable* old_context,
-                          LocalVariable* iterator_param,
-                          const intptr_t old_ctx_level,
-                          JoinEntryInstr* target);
-
-  void BuildAsyncJump(LocalVariable* old_context,
-                      LocalVariable* continuation_result,
-                      LocalVariable* continuation_error,
-                      LocalVariable* continuation_stack_trace,
-                      const intptr_t old_ctx_level,
-                      JoinEntryInstr* target);
-
   void BuildInstanceGetterConditional(InstanceGetterNode* node);
   void BuildInstanceCallConditional(InstanceCallNode* node);