ART: Fix JDWP GetClassLoader command

The command is spec-ed to take a type, and return the type's
classloader. The input is thus already a Class, not a generic Object.
Fix the implementation to not always return null.

Bug: 26349019
Change-Id: I4aa075902f4a112624edc644d3540a59eea057c8
diff --git a/runtime/ b/runtime/
index e0211f5..f009fe6 100644
--- a/runtime/
+++ b/runtime/
@@ -730,7 +730,8 @@
   if (o == nullptr) {
-  expandBufAddObjectId(pReply, gRegistry->Add(o->GetClass()->GetClassLoader()));
+  DCHECK(o->IsClass());
+  expandBufAddObjectId(pReply, gRegistry->Add(o->AsClass()->GetClassLoader()));
   return JDWP::ERR_NONE;