Fix infinite loop with MATCH_INVALID_UTF in PCRE2 <10.36

[straight-shoota]

The MATCH_INVALID_UTF8 flag was introduced in PCRE2 10.34 but it has a bug that can lead to infinite loops. This bug is fixed in 10.36 and we should not use this flag with affected versions.

Fixes #13306

[HertzDevil]

The infinite loop recreated in Crystal:

# prints only 0 on PCRE 10.34 and 10.35, proceeds on 10.36+
(0..).each do |i|
  p i
  "\u{e7}#a" =~ /^.a/m
end

Locally I could confirm that a JIT-enabled PCRE2 10.36 runs make docs correctly whereas 10.35 gets stuck without this patch.

Some Regex specs need their version checks replaced (Regex::Engine.version_number < {10, 34} etc.).

[beta-ziliani]

There is one more spec with < 10.35 that probably should be bumped to 10.36