Add PCRE Performance Testing

[miqrogroove]

The script I've been using for PCRE performance testing is now getting released as a phpUnit utility. Details to follow...

[miqrogroove]

In 34121.diff​:

• Move pattern from wptexturize() into a separate function.
• Move pattern from wp_html_split() into a separate function.
• Beautify code for wp_html_split().
• Remove unnecessary instances of /s modifier in patterns that don't use dots.
• Add tests/phpunit/data/formatting/whole-posts.php for testing larger strings.
• Add function benchmark_pcre_backtracking().
• Add tests for wp_html_split().
• Add tests for wptexturize().
• Add tests for get_shortcode_regex().

[wonderboymusic]

In 34761:

Shortcodes/Formatting: Add PCRE Performance Testing

• Move pattern from wptexturize() into a separate function.
• Move pattern from wp_html_split() into a separate function.
• Beautify code for wp_html_split().
• Remove unnecessary instances of /s modifier in patterns that don't use dots.
• Add tests/phpunit/data/formatting/whole-posts.php for testing larger strings.
• Add function benchmark_pcre_backtracking().
• Add tests for wp_html_split().
• Add tests for wptexturize().
• Add tests for get_shortcode_regex().

Props miqrogroove.
Fixes #34121.

[miqrogroove]

Looks like we missed a file there :) I want to tweak the new benchmark function anyway so patch coming up briefly.

[miqrogroove]

Missing parts

[boonebgorges]

In 34772:

Fix preg_match_all() syntax in PCRE benchmark test util.

In versions of PHP earlier than 5.4, the $matches parameter was required.
Excluding it here meant that PCRE benchmarking tests were erroring on older
versions of PHP without cleaning up the PCRE ini settings, causing various
problems on later tests.

Props miqrogroove, dd32, boonebgorges.

And to the cosmic forces that cause bugs like this. The best part of waking up
is diagnosing leakage between automated tests.

See #34121.

[boonebgorges]

In 34773:

Improvements to PCRE benchmarking tests.

• Add test file accidentally omitted from [34761].
• Bail properly from benchmarker when a preg_last_error() is found.

Props miqrogroove.
See #34121.

[miqrogroove]

Fixed by [34761], [34772], and [34773]