Implement new optional parameters syntax in the vm (issue 4290).

runtime/vm/flow_graph.h

Index: runtime/vm/flow_graph.h
===================================================================
--- runtime/vm/flow_graph.h	(revision 11998)
+++ runtime/vm/flow_graph.h	(working copy)
@@ -49,19 +49,19 @@
     return parsed_function_;
   }
   intptr_t parameter_count() const {
-    return copied_parameter_count_ + non_copied_parameter_count_;
+    return num_copied_params_ + num_non_copied_params_;
   }
   intptr_t variable_count() const {
-    return parameter_count() + stack_local_count_;
+    return parameter_count() + num_stack_locals_;
   }
-  intptr_t stack_local_count() const {
-    return stack_local_count_;
+  intptr_t num_stack_locals() const {
+    return num_stack_locals_;
   }
-  intptr_t copied_parameter_count() const {
-    return copied_parameter_count_;
+  intptr_t num_copied_params() const {
+    return num_copied_params_;
   }
-  intptr_t non_copied_parameter_count() const {
-    return non_copied_parameter_count_;
+  intptr_t num_non_copied_params() const {
+    return num_non_copied_params_;
   }
 
   // Flow graph orders.
@@ -154,9 +154,9 @@
 
   // Flow graph fields.
   const ParsedFunction& parsed_function_;
-  const intptr_t copied_parameter_count_;
-  const intptr_t non_copied_parameter_count_;
-  const intptr_t stack_local_count_;
+  const intptr_t num_copied_params_;
+  const intptr_t num_non_copied_params_;
+  const intptr_t num_stack_locals_;
   GraphEntryInstr* graph_entry_;
   GrowableArray<BlockEntryInstr*> preorder_;
   GrowableArray<BlockEntryInstr*> postorder_;