Refactor HType to get rid of various hacks.

src/arm64/lithium-arm64.cc

Index: src/arm64/lithium-arm64.cc
diff --git a/src/arm64/lithium-arm64.cc b/src/arm64/lithium-arm64.cc
index f434e466cd25e45a7d16ce2b89cccd232bcd87f2..d365dcf96cf29faf0e33c1e80b3906b0abb4fd63 100644
--- a/src/arm64/lithium-arm64.cc
+++ b/src/arm64/lithium-arm64.cc
@@ -1216,7 +1216,9 @@ LInstruction* LChunkBuilder::DoCheckMaps(HCheckMaps* 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;
 }