Fix oatdump to use OatHeader pointer size

Bug: 18473190
Change-Id: If505b4f62105899f4f1257d3bccda3e6eb0dcd7c

(cherry picked from commit c934e483ceabbd589422beea1fa35f5182ecfa99)
diff --git a/runtime/fault_handler.cc b/runtime/fault_handler.cc
index ab3ec62..835485c 100644
--- a/runtime/fault_handler.cc
+++ b/runtime/fault_handler.cc
@@ -360,7 +360,8 @@
   // at the return PC address.
   if (true || kIsDebugBuild) {
     VLOG(signals) << "looking for dex pc for return pc " << std::hex << return_pc;
-    const void* code = Runtime::Current()->GetInstrumentation()->GetQuickCodeFor(method_obj);
+    const void* code = Runtime::Current()->GetInstrumentation()->GetQuickCodeFor(method_obj,
+                                                                                 sizeof(void*));
     uint32_t sought_offset = return_pc - reinterpret_cast<uintptr_t>(code);
     VLOG(signals) << "pc offset: " << std::hex << sought_offset;
   }