replace various sv_catpv(sv,"cstr") calls with len counted calls

[bulk88]

-perf reasons, even though I guess most of the code is rarely called since they are error branches, do it anyways, it is only 1 more assembly op (2-4 bytes) vs not including len, and skips strlen() overhead

-GDBM_File.xs -'sv_catpv(sv, ": ");' gdbm: Define error codes; provide the global $gdbm_errno variable. 8b8b12225a4af2826a4714f04e9f7464766199c6 10/11/2021 11:58:44 AM

regcomp.c -'sv_catpv(substitute_parse, ")");' -"sv_catpv(substitute_parse, SvPVX(this_sequence));" len is known, its an an SV with contents gen by core, probably from regexp pl code, if it was passing control codes to console on the regular, I assume that would've been fixed long ago, therefore we not trying eliminate user's null chars 9d53c4576e551530162e7cd79ab72ed81b1e1a0f 10/11/2012 11:49:31 PM PATCH: [perl #89774] multi-char fold + its fold in char class

-'const char overflow_msg[] = "Code point' This was creating uncond a RW array on C stack from a RO global string, then sometimes passing ptr to C stk alloced array, to sv_catpv() -"sv_catpv(msg, prefix);" pass len to RO string 73b95840bb1b55d761ec2dd075d2a8c37fa94bf4 8/20/2018 8:31:04 PM Move \p{user-defined} to core from utf8_heavy.pl

-mg.c Revision: b35e4f8b3f15f0474d08f63e1f479787e261f485 12/14/2013 9:48:00 PM Fix HP-UX $! failure -"sv_catpv(sv, UNKNOWN_ERRNO_MSG);" is a const literal

-perlio.c -add comment about the unusual but correct stack array, its length can be const computed so do it

-pp_ctl.c 46fc3d4c69a0adf236bfcba70daee7fd597cf30d 4/22/1997 8:00:00 AM [inseparable changes from match from perl-5.003_97g to perl-5.003_97h] -"sv_catpv(namesv, unixname);" seems to be left over after converting this area of code from an unsafe "strcat()" design, use len since we know it

TODO: fill description here

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• This set of changes requires a perldelta entry, and it is included.
• This set of changes requires a perldelta entry, and I need help writing it.
• This set of changes does not require a perldelta entry.