Revert "Revert "Use the object class as top in reference type propagation""

This reverts commit 7733bd644ac71f86d4b30a319624b23343882e53.

Change-Id: I7d393a808c01c084c18d632a54e0554b4b455f2c
diff --git a/compiler/optimizing/inliner.cc b/compiler/optimizing/inliner.cc
index c185b58..644f45c 100644
--- a/compiler/optimizing/inliner.cc
+++ b/compiler/optimizing/inliner.cc
@@ -109,10 +109,8 @@
     receiver = receiver->InputAt(0);
   }
   ReferenceTypeInfo info = receiver->GetReferenceTypeInfo();
-  if (info.IsTop()) {
-    // We have no information on the receiver.
-    return nullptr;
-  } else if (!info.IsExact()) {
+  DCHECK(info.IsValid()) << "Invalid RTI for " << receiver->DebugName();
+  if (!info.IsExact()) {
     // We currently only support inlining with known receivers.
     // TODO: Remove this check, we should be able to inline final methods
     // on unknown receivers.