Trivial bounds checking.

Bounds checking strpy, strcat and sprintf.
These are the remaining easy ones to cover a recently removed commit.
Some are trivial, some have been modified and a couple left as they are because the reverted change didn't bounds check properly.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3871)