Clean up the runtime read barrier and fix fake address dependency.

- Rename GetReadBarrierPointer to GetReadBarrierState.
- Change its return type to uint32_t.
- Fix the runtime fake address dependency for arm/arm64 using inline
  asm.
- Drop ReadBarrier::black_ptr_ and some brooks code.

Bug: 12687968
Test: test-art with CC, Ritz EAAC, libartd boot on N9.
Change-Id: I595970db825db5be2e98ee1fcbd7696d5501af55
diff --git a/patchoat/patchoat.cc b/patchoat/patchoat.cc
index 986f265..7ea5bea 100644
--- a/patchoat/patchoat.cc
+++ b/patchoat/patchoat.cc
@@ -747,13 +747,8 @@
 void PatchOat::VisitObject(mirror::Object* object) {
   mirror::Object* copy = RelocatedCopyOf(object);
   CHECK(copy != nullptr);
-  if (kUseBakerOrBrooksReadBarrier) {
-    object->AssertReadBarrierPointer();
-    if (kUseBrooksReadBarrier) {
-      mirror::Object* moved_to = RelocatedAddressOfPointer(object);
-      copy->SetReadBarrierPointer(moved_to);
-      DCHECK_EQ(copy->GetReadBarrierPointer(), moved_to);
-    }
+  if (kUseBakerReadBarrier) {
+    object->AssertReadBarrierState();
   }
   PatchOat::PatchVisitor visitor(this, copy);
   object->VisitReferences<kVerifyNone>(visitor, visitor);