Revert "minor #11808 [Security] Add more tests for StringUtils::equals (dunglas)"

This reverts commit 8fdfb6fc35e194db06583854933f9c826608f7a7, reversing
changes made to e99dfdf87a8f0d2871a5415401409ed96cff6f3d.
Merge branch '2.4' into 2.5

* 2.4:
  Revert "minor #11808 [Security] Add more tests for StringUtils::equals (dunglas)"