[5.5] Fix PHP error in operatorForWhere collection method.

[mathieutu]

Hi,
When you compare thing in collection (contains, every and where), if arguments are not comparable, php will throw an error.

Example:

collect([['v' => 1], ['v' => new stdClass]])->where('v', 1);

This PR fix that, and add some tests to check it.

[GrahamCampbell]

Have you tested this works?

[mathieutu]

@GrahamCampbell I did, and I even wrote an unit test for that.
The test will fail if you remove the try/catch.
😉