Fix x64 patching of asllocation stub: the pool pointer must be set-up before patching jump is execu…

runtime/vm/compiler_test.cc

Index: runtime/vm/compiler_test.cc
===================================================================
--- runtime/vm/compiler_test.cc	(revision 40327)
+++ runtime/vm/compiler_test.cc	(working copy)
@@ -101,6 +101,15 @@
   owner.SwitchAllocationStub();
   result = Dart_Invoke(lib, NewString("main"), 0, NULL);
   EXPECT_VALID(result);
+
+  owner.SwitchAllocationStub();
+  result = Dart_Invoke(lib, NewString("main"), 0, NULL);
+  EXPECT_VALID(result);
+
+  owner.SwitchAllocationStub();
+  result = Dart_Invoke(lib, NewString("main"), 0, NULL);
+  EXPECT_VALID(result);
+
   FLAG_enable_type_checks = old_enable_type_checks;
 }