Type conversion elimination of constants

A better way of eliminating type conversion for constants.

Test: run-test on host. 711-checker-type-conversion.
Change-Id: I457bc091542a5ac4cc4e77cadb012ee7cb040ce8
diff --git a/compiler/optimizing/constant_folding.cc b/compiler/optimizing/constant_folding.cc
index bb586bf..6f11e62 100644
--- a/compiler/optimizing/constant_folding.cc
+++ b/compiler/optimizing/constant_folding.cc
@@ -113,7 +113,7 @@
 void HConstantFoldingVisitor::VisitTypeConversion(HTypeConversion* inst) {
   // Constant folding: replace `TypeConversion(a)' with a constant at
   // compile time if `a' is a constant.
-  HConstant* constant = inst->AsTypeConversion()->TryStaticEvaluation();
+  HConstant* constant = inst->TryStaticEvaluation();
   if (constant != nullptr) {
     inst->ReplaceWith(constant);
     inst->GetBlock()->RemoveInstruction(inst);