[ptr-compr] Fix macro assembler test for CFI failure

Use the GeneratedCode construct in the EmbeddedObj test to ensure
clang with cfi support is happy.

Bug: v8:7703
Change-Id: Ib80add62127049ee5a763c6a4320add11682395d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1611537Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61470}

test/cctest/test-macro-assembler-x64.cc

@@ -454,9 +454,9 @@ TEST(EmbeddedObj) {
   StdoutStream os;
   code->Print(os);
 #endif
-  typedef int64_t (*myF0)();
-  myF0 f = FUNCTION_CAST<myF0>(code->entry());
-  Object result = static_cast<Object>(f());
+  typedef Object(myF0)();
+  auto f = GeneratedCode<myF0>::FromAddress(isolate, code->entry());
+  Object result = f.Call();
   CHECK_EQ(old_array->ptr(), result.ptr());
 
   // Collect garbage to ensure reloc info can be walked by the heap.