Use same range info when emitting code and computing if instruction can deopt.

runtime/vm/flow_graph_type_propagator.cc

Index: runtime/vm/flow_graph_type_propagator.cc
diff --git a/runtime/vm/flow_graph_type_propagator.cc b/runtime/vm/flow_graph_type_propagator.cc
index a11c33b700374a3c391fb7969896338c0de287b0..7f279edc8ed8ff49616e034f574394890c6caa76 100644
--- a/runtime/vm/flow_graph_type_propagator.cc
+++ b/runtime/vm/flow_graph_type_propagator.cc
@@ -1518,7 +1518,7 @@ CompileType InvokeMathCFunctionInstr::ComputeType() const {
 }
 
 
-CompileType MergedMathInstr::ComputeType() const {
+CompileType TruncDivModInstr::ComputeType() const {
   return CompileType::Dynamic();

[rmacnak, 2017/05/18 20:02:45]

Smi?, though I don't think it affects anything since the ExtractOutput was
already told it was Smi.

[Vyacheslav Egorov (Google), 2017/05/19 08:07:08]

TruncDivModInstr returns a tuple - a pair of Smi-s - so we can't declare it
returns a smi :) Strictly speaking it returns something that can't be considered
singular Dart value. Hence we have no type here.

 }