Pushes 0 for PC marker in runtime call stubs on ARM and MIPS.

runtime/vm/stack_frame.cc

Index: runtime/vm/stack_frame.cc
===================================================================
--- runtime/vm/stack_frame.cc	(revision 30526)
+++ runtime/vm/stack_frame.cc	(working copy)
@@ -97,14 +97,18 @@
       // Spill slots are at the 'bottom' of the frame.
       intptr_t spill_slot_count = length - map.RegisterBitCount();
       for (intptr_t bit = 0; bit < spill_slot_count; ++bit) {
-        if (map.IsObject(bit)) visitor->VisitPointer(last);
+        if (map.IsObject(bit)) {
+          visitor->VisitPointer(last);
+        }
         --last;
       }
 
       // The live registers at the 'top' of the frame comprise the rest of the
       // stack map.
       for (intptr_t bit = length - 1; bit >= spill_slot_count; --bit) {
-        if (map.IsObject(bit)) visitor->VisitPointer(first);
+        if (map.IsObject(bit)) {
+          visitor->VisitPointer(first);
+        }
         ++first;
       }