Improve performance of Loop by avoiding unneeded method calls

[clue]

This changeset improves performance of Loop slightly by avoiding unneeded method calls. Not the most significant improvement, but given the small changeset and how we plan to make the default Loop more prominent in ReactPHP v3, I figured this change makes sense in either case:

$ time php examples/91-benchmark-ticks.php 1000000
// old 0.83
// new 0.76

Builds on top of #245 and #229
See also https://github.com/orgs/reactphp/discussions/481

[clue]

Updated to work around all legacy PHP and Windows quirks, the result is a somewhat less compact changeset, but still shows the same performance improvements. One more reason to drop legacy support in upcoming ReactPHP v3 (https://github.com/orgs/reactphp/discussions/481) to simplify this significantly! This is ready for review.

[WyriHaximus]

Not as pretty as we discussed earlier this week, but a good step to improve performance for this 👍