Rollup merge of #118083 - calebzulawski:remove-i686-apple-darwin, r=albertlarsan68

Remove i686-apple-darwin cross-testing

The Xcode SDK no longer ships with 32-bit Intel (i686-apple-darwin) support as of [Xcode 14](https://developer.apple.com/news/upcoming-requirements/?id=06062022a) (related, #112753).  On an up-to-date Intel Mac, `x.py test --bless` fails.

r? ``@rust-lang/bootstrap``

Author: Noratrieb