ART: Rename Handle hierarchy

Bring the names in line with normal OO principles: ConstHandle
becomes Handle, and Handle becomes MutableHandle.

Change-Id: I0f018eb7ba28bc422e3a23dd73a6cbe6fc2d2044
diff --git a/runtime/transaction_test.cc b/runtime/transaction_test.cc
index 8c37489..432a2fe 100644
--- a/runtime/transaction_test.cc
+++ b/runtime/transaction_test.cc
@@ -460,7 +460,7 @@
 
   // Load and verify java.lang.ExceptionInInitializerError and java.lang.InternalError which will
   // be thrown by class initialization due to native call.
-  Handle<mirror::Class> h_klass(
+  MutableHandle<mirror::Class> h_klass(
       hs.NewHandle(class_linker_->FindSystemClass(soa.Self(),
                                                   "Ljava/lang/ExceptionInInitializerError;")));
   ASSERT_TRUE(h_klass.Get() != nullptr);