Suppress cast-function-type in PersistentBase::SetWeak

This issue was seen in Node.js when compiling with GCC. It can also
been see if building V8 using GCC and enabling -Wcast-function-type
in BUILD.gn:
  "-Wcast-function-type",

There are unit tests in V8 that produce this warning, for example
test/cctest/test-global-handles.cc (formatted to fit the commit
message width):
g++ -MMD -MF obj/test/cctest/cctest_sources/test-global-handles.o.d
...
In file included from ../../include/v8-inspector.h:14,
                 from ../../src/execution/isolate.h:15,
                 from ../../src/api/api.h:10,
                 from ../../src/api/api-inl.h:8,
                 from ../../test/cctest/test-global-handles.cc:28:
../../include/v8.h:
In instantiation of ‘void v8::PersistentBase<T>::SetWeak(
    P*,
    typename v8::WeakCallbackInfo<P>::Callback,
    v8::WeakCallbackType)
[with
  P = v8::Global<v8::Object>;
  T = v8::Object;
  typename v8::WeakCallbackInfo<P>::Callback =
  void (*)(const v8::WeakCallbackInfo<v8::Global<v8::Object> >&)
]’:
../../test/cctest/test-global-handles.cc:292:47: required from here
../../include/v8.h:10750:16: warning:
cast between incompatible function types from
‘v8::WeakCallbackInfo<v8::Global<v8::Object> >::Callback’ {aka
‘void (*)(const v8::WeakCallbackInfo<v8::Global<v8::Object> >&)’} to
‘Callback’ {aka ‘void (*)(const v8::WeakCallbackInfo<void>&)’}
[-Wcast-function-type]
10750 |                reinterpret_cast<Callback>(callback), type);
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This commit suggests adding a pragma specifically for GCC to suppress
this warning.

Bug: v8:8735
Change-Id: I5dd2dccf215a7fd2f6dd14993368cc5cbb6c71e5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2080361
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68320}

include/v8.h

@@ -10811,8 +10811,15 @@ V8_INLINE void PersistentBase<T>::SetWeak(
     P* parameter, typename WeakCallbackInfo<P>::Callback callback,
     WeakCallbackType type) {
   typedef typename WeakCallbackInfo<void>::Callback Callback;
+#if (__GNUC__ >= 8) && !defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-function-type"
+#endif
   V8::MakeWeak(reinterpret_cast<internal::Address*>(this->val_), parameter,
                reinterpret_cast<Callback>(callback), type);
+#if (__GNUC__ >= 8) && !defined(__clang__)
+#pragma GCC diagnostic pop
+#endif
 }
 
 template <class T>