Allow catch-int to be nolinted

Summary:
Add a hidden nolint option to suppress this lint warning. It is
appropriate in this case.

Test Plan:
Build flint, run it on ExceptionWrapperTest.cpp, see no catch
lint failure

Reviewed By: andrei.alexandrescu@fb.com

Subscribers: sdwilsh, louisk, njormrod, folly-diffs@

FB internal diff: D1644165

Tasks: 5486739

Signature: t1:1644165:1414616664:a6b9dc34660df84b33ed8faaf48ec048a02bad01

folly/test/ExceptionWrapperTest.cpp

@@ -210,7 +210,7 @@ TEST(ExceptionWrapper, non_std_exception_test) {
   // access their value is to explicity rethrow and catch it.
   try {
     ew.throwException();
-  } catch (int& i) {
+  } catch /* nolint */ (int& i) {
     EXPECT_EQ(i, expected);
   }
 }