ext/standard: applied fixers to improve test robustness

[NickSdot]

Asserts error class; extracted from: #22799

GitHub is lagging this, easier to review with: https://diffshub.com/php/php-src/pull/23136

[NickSdot]

@bukka following your comment yesterday I reviewed this one once again, and wanted to double check.

1. Out of 4,210 total lines, 13 (in 4 files) are affected by the same style-only thematic. Are you here okay with unifying those 13 lines with the rest or do you want me to make a manual follow up?
2. And while we are on it... Currently line endings are untouched; some said output always should be \n, others don't wanted them to be touched. Would you prefer to convert to \n or nah?

I would make a manual follow up to get these addressed.

Files affected by the style-only thematic:
ext/standard/tests/array/gh22678.phpt
ext/standard/tests/filters/gh20370.phpt
ext/standard/tests/strings/gh20906_1.phpt
ext/standard/tests/strings/setlocale_null_byte.phpt