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/thread.cc b/runtime/thread.cc
index d4ac02b..c54bebe 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -446,7 +446,7 @@
 
   ScopedObjectAccess soa(self);
   StackHandleScope<1> hs(self);
-  Handle<mirror::String> peer_thread_name(hs.NewHandle(GetThreadName(soa)));
+  MutableHandle<mirror::String> peer_thread_name(hs.NewHandle(GetThreadName(soa)));
   if (peer_thread_name.Get() == nullptr) {
     // The Thread constructor should have set the Thread.name to a
     // non-null value. However, because we can run without code