Refactor HType to get rid of various hacks.

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index 8a52f7b45352cdf7c24349ba7b50d142cf723a7e..1525565f190c084eee9a23760bbaadca76b71183 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -1979,7 +1979,9 @@ LInstruction* LChunkBuilder::DoChange(HChange* instr) {
 LInstruction* LChunkBuilder::DoCheckHeapObject(HCheckHeapObject* instr) {
   LOperand* value = UseRegisterAtStart(instr->value());
   LInstruction* result = new(zone()) LCheckNonSmi(value);
-  if (!instr->value()->IsHeapObject()) result = AssignEnvironment(result);
+  if (!instr->value()->type().IsHeapObject()) {
+    result = AssignEnvironment(result);
+  }
   return result;
 }