[assembler] Remove unnecessary cast.

src/arm64/assembler-arm64-inl.h

Index: src/arm64/assembler-arm64-inl.h
diff --git a/src/arm64/assembler-arm64-inl.h b/src/arm64/assembler-arm64-inl.h
index a87d94ef34265272630a7f0df8f3d1a9dbd5911b..de7e71df7322344d9af8211726ffeff6dcf7a5d4 100644
--- a/src/arm64/assembler-arm64-inl.h
+++ b/src/arm64/assembler-arm64-inl.h
@@ -813,9 +813,9 @@ void RelocInfo::set_debug_call_address(Address target) {
   STATIC_ASSERT(Assembler::kPatchDebugBreakSlotAddressOffset == 0);
   Assembler::set_target_address_at(isolate_, pc_, host_, target);
   if (host() != NULL) {
-    Object* target_code = Code::GetCodeFromTargetAddress(target);
-    host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(
-        host(), this, HeapObject::cast(target_code));
+    Code* target_code = Code::GetCodeFromTargetAddress(target);
+    host()->GetHeap()->incremental_marking()->RecordWriteIntoCode(host(), this,
+                                                                  target_code);
   }
 }