Mark isolate2_negative_test as flaky.

tests/isolate/isolate.status

Index: tests/isolate/isolate.status
diff --git a/tests/isolate/isolate.status b/tests/isolate/isolate.status
index fac18365f9bb841df4e56943ff6d1d22ed046498..1fc189dea141fe8f93b6b9f55f80108fa300437f 100644
--- a/tests/isolate/isolate.status
+++ b/tests/isolate/isolate.status
@@ -89,9 +89,7 @@ spawn_uri_vm_test: Skip # test uses a ".dart" suffix that only works in vm.
 spawn_uri_vm_negative_test: Skip # ditto above.
 timer_not_available_test: Fail, OK # only meant to test when there is no way to
                                    # implement timer (currently only in d8)
-
-[ $compiler == dart2js && ($runtime == drt || $runtime == chrome || ($runtime == ff && $system == linux)) ]
-isolate2_negative_test: Fail # Issue 7769
+isolate2_negative_test: Fail, Pass # Issue 7769
 
 [ $compiler == dart2js && $jscl ]
 multiple_timer_test: Fail,OK # Needs Timer to run.