Improve detection of suspicious uses of bidi controls

Improve detection of suspicious uses of bidi controls

* lisp/international/textsec.el
(textsec-bidi-controls-suspicious-p): New function.
(textsec-name-suspicious-p): Use it.

* test/lisp/international/textsec-tests.el (test-suspicious-name):
Enable the test that was previously failing with
'bidi-find-overridden-directionality'.