Iterate over PcDescriptors only via iterators, not via an index. (preparation for more compression …

runtime/vm/flow_graph_builder.cc

Index: runtime/vm/flow_graph_builder.cc
===================================================================
--- runtime/vm/flow_graph_builder.cc	(revision 37788)
+++ runtime/vm/flow_graph_builder.cc	(working copy)
@@ -1010,7 +1010,7 @@
   if ((node->token_pos() != Scanner::kNoSourcePos) &&
       !function.is_native() && FLAG_enable_debugger) {
     AddInstruction(new DebugStepCheckInstr(node->token_pos(),
-                                           PcDescriptors::kRuntimeCall));
+                                           RawPcDescriptors::kRuntimeCall));
   }
 
   if (FLAG_enable_type_checks) {
@@ -3110,7 +3110,7 @@
       node->value()->IsLoadLocalNode()) {
     if (FLAG_enable_debugger) {
       AddInstruction(new DebugStepCheckInstr(node->token_pos(),
-                                             PcDescriptors::kRuntimeCall));
+                                             RawPcDescriptors::kRuntimeCall));
     }
   }