Various improvements to stack walking speed

Make BitMemoryRegion constructor inlined, remove read barrier
for IsProxyMethod.

Around 15% speedup for pmd benchmark, maybe more for CC.

Test: test-art-host

Change-Id: Ib4392649e041406e538cc944c26c69f68d388fb4
diff --git a/runtime/art_method-inl.h b/runtime/art_method-inl.h
index 7ec3900..950f1aa 100644
--- a/runtime/art_method-inl.h
+++ b/runtime/art_method-inl.h
@@ -374,9 +374,10 @@
   }
 }
 
-template<ReadBarrierOption kReadBarrierOption>
 inline bool ArtMethod::IsProxyMethod() {
-  return GetDeclaringClass<kReadBarrierOption>()->IsProxyClass();
+  // Avoid read barrier since the from-space version of the class will have the correct proxy class
+  // flags since they are constant for the lifetime of the class.
+  return GetDeclaringClass<kWithoutReadBarrier>()->IsProxyClass();
 }
 
 inline ArtMethod* ArtMethod::GetInterfaceMethodIfProxy(PointerSize pointer_size) {