[gardening] Fix httpIG sample test, update new isolate_group_bound test status on fuchsia.

Fix failures https://dart-ci.appspot.com/log/vm-linux-release-x64/vm-linux-release-x64/6082/samples/ffi/httpIG/test/http_test

Lift .status-file constraints on where http and httpIG samples can run.

Follow-up to b759d096cb
TEST=ci

Change-Id: Icc71d6407e910d30f6ff028830550a05b179f1da
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/444927
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>

samples/ffi/httpIG/lib/http.dart

@@ -12,7 +12,7 @@ import 'package:ffi/ffi.dart';
 
 import 'dylib_utils.dart';
 
-Function (Pointer<Utf8>) createGetSender(SendPort sendPort) {
+Function (Pointer<Utf8>) createGetSender(final SendPort sendPort) {
   return (Pointer<Utf8> responsePointer) {
     final typedList = responsePointer.cast<Uint8>().asTypedList(
           responsePointer.length,
@@ -57,7 +57,7 @@ Future<String> httpGet(String uri) async {
 @pragma('vm:shared')
 late int counter;
 
-Function (Pointer<Utf8>) createServeSender(SendPort sendPort) {
+Function (Pointer<Utf8>) createServeSender(final SendPort sendPort) {
   return (Pointer<Utf8> requestPointer) {
     counter++;
     final typedList = requestPointer.cast<Uint8>().asTypedList(