Simplify constant pool usage in x64 code generator (by removing extra argument

runtime/vm/object_x64_test.cc

Index: runtime/vm/object_x64_test.cc
diff --git a/runtime/vm/object_x64_test.cc b/runtime/vm/object_x64_test.cc
index b8914e0ab274737fe76e98587356b2b350e61f05..6193e0bb1e531d7a9a263fd3c66e077e6fc0d4b8 100644
--- a/runtime/vm/object_x64_test.cc
+++ b/runtime/vm/object_x64_test.cc
@@ -36,7 +36,7 @@ void GenerateEmbedStringInCode(Assembler* assembler, const char* str) {
       String::ZoneHandle(String::New(str, Heap::kOld));
   __ pushq(PP);  // Save caller's pool pointer and load a new one here.
   __ LoadPoolPointer(PP);
-  __ LoadObject(RAX, string_object, PP);
+  __ LoadObject(RAX, string_object);
   __ popq(PP);  // Restore caller's pool pointer.
   __ ret();
 }