Various tests construct UTCDateTimes from 64-bit integer literals, and do so without a SKIPIF check for PHP_INT_SIZE. For compatibility with 32-bit platforms, we should change these tests to use smaller integers or numeric strings (UTCDateTime's constructor will parse strings as 64-bit numbers).

Note: the fact that we haven't noticed failures in these tests before suggests that they may not be running on a 32-bit platform in our matrix – or they are and passing for some other unknown reason.

More generically, we may want to repurpose this ticket to audit the test suite for any instance of numeric literals exceeding the range of 32-bit signed integers.