PHP 8.6 | Tests: further changes to handle a change in error message format

[antecedent]

This is meant to bring #217 to completion. I merged that one prematurely; the test case had not been passing.

[jrfnl]

@antecedent Interesting. I'd run the tests locally on Windows with PHP 8.6-beta1 with a php.ini based on the php.ini-development file and the tests were passing fine.
And while I'm writing this, I remember that shivammathur/setup-php uses the php.ini-production file as default, so it makes total sense that the ini values for the settings being changed in this PR would be turned off for production.

In other words, an alternative solution would probably be to add ini-file: development to the with section of the Setup PHP step.

Not sure what you would prefer ?

[antecedent]

@jrfnl, I think that is great! I do prefer having the php.ini values set in a more across-the-board way. But it was not enough to set ini-file: development; I ended up adding the setting to ini-values separately. That is still an improvement to me. But I wonder how come you got a different default from the php.ini-development on your local setup 👀