Reapply "Deoptimization support in inlined code."

runtime/vm/il_printer.cc

Index: runtime/vm/il_printer.cc
diff --git a/runtime/vm/il_printer.cc b/runtime/vm/il_printer.cc
index 07abcf71799c6dd3f18658b2b1d11932deaab52b..2f1247a377f3e8424c61a1550dd70443a9c56167 100644
--- a/runtime/vm/il_printer.cc
+++ b/runtime/vm/il_printer.cc
@@ -787,9 +787,14 @@ void ParallelMoveInstr::PrintToVisualizer(BufferFormatter* f) const {
 
 void Environment::PrintTo(BufferFormatter* f) const {
   f->Print(" env={ ");
+  int arg_count = 0;
   for (intptr_t i = 0; i < values_.length(); ++i) {
     if (i > 0) f->Print(", ");
-    values_[i]->PrintTo(f);
+    if (values_[i]->definition()->IsPushArgument()) {
+      f->Print("a%d", arg_count++);
+    } else {
+      values_[i]->PrintTo(f);
+    }
     if ((locations_ != NULL) && !locations_[i].IsInvalid()) {
       f->Print(" [");
       locations_[i].PrintTo(f);