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

This reverts commit 3fabec7a25d151b26ba7de13615bbead0dd615a6.

Change-Id: Id8614f6b6e3e0e4c9caeb9f771e4c145d9fec64f
diff --git a/compiler/optimizing/inliner.cc b/compiler/optimizing/inliner.cc
index 860b199..3efe7c7 100644
--- a/compiler/optimizing/inliner.cc
+++ b/compiler/optimizing/inliner.cc
@@ -109,8 +109,10 @@
     receiver = receiver->InputAt(0);
   }
   ReferenceTypeInfo info = receiver->GetReferenceTypeInfo();
-  DCHECK(info.IsValid()) << "Invalid RTI for " << receiver->DebugName();
-  if (!info.IsExact()) {
+  if (info.IsTop()) {
+    // We have no information on the receiver.
+    return nullptr;
+  } else 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.