Put PushArgument into the environment instead of raw values.

runtime/vm/deopt_instructions.cc

Index: runtime/vm/deopt_instructions.cc
diff --git a/runtime/vm/deopt_instructions.cc b/runtime/vm/deopt_instructions.cc
index 9c959f8bb35c623dc39216a41fd74a8912d40b84..1f7b4911904485082c0581c0a8eac0f000408b4a 100644
--- a/runtime/vm/deopt_instructions.cc
+++ b/runtime/vm/deopt_instructions.cc
@@ -227,11 +227,13 @@ void DeoptInfoBuilder::AddCopy(const Location& from_loc,
     deopt_instr = new DeoptRegisterInstr(from_loc.reg());
   } else if (from_loc.IsStackSlot()) {
     deopt_instr = new DeoptStackSlotInstr(from_loc.stack_index() + num_args_);
-  } else if (from_loc.IsInvalid()) {
-    ASSERT(from_value.IsConstant());
+  } else if (from_loc.IsInvalid() && from_value.IsConstant()) {
     const Object& obj = from_value.AsConstant()->value();
     intptr_t object_table_index = FindOrAddObjectInTable(obj);
     deopt_instr = new DeoptConstantInstr(object_table_index);
+  } else if (from_loc.IsInvalid()) {
+    ASSERT(from_value.AsUse()->definition()->IsPushArgument());
+    deopt_instr = new DeoptStackSlotInstr(PushArgument() + num_args_);
   } else {
     UNREACHABLE();
   }