Do not invoke fatal in dart:_internal when fuzzing mirrors

tests/lib/mirrors/invocation_fuzz_test.dart

Index: tests/lib/mirrors/invocation_fuzz_test.dart
diff --git a/tests/lib/mirrors/invocation_fuzz_test.dart b/tests/lib/mirrors/invocation_fuzz_test.dart
index 8add257d7a99686e2217150910c00909a4f7db8d..1043145218327f17cc4705dfef871550ed1a140b 100644
--- a/tests/lib/mirrors/invocation_fuzz_test.dart
+++ b/tests/lib/mirrors/invocation_fuzz_test.dart
@@ -50,6 +50,8 @@ var blacklist = [
   // Don't call private methods in dart.async as they may circumvent the zoned
   // error handling below.
   new RegExp(r"^dart\.async\._.*$"),
+
+  'dart._internal.fatal',
 ];
 
 bool isBlacklisted(Symbol qualifiedSymbol) {