Options, Meta APIs: Rename option cache priming functions.
Rename the option cache priming functions to more closely follow the naming convention used by other cache priming functions.
wp_load_options() becomes wp_prime_option_caches()
wp_load_options_by_group() becomes wp_prime_option_caches_by_group()
The unit test files and classes are renamed accordingly.
Unlike the existing cache priming functions, these functions were introduced with the intention of being public so use the wp_ prefix rather than the _ prefix used by the functions initially introduced as private functions but since made public.
Follow up to [56445],[56990].
Props flixos90, peterwilsoncc, joemcgill, SergeyBiryukov, desrosj.
Reviewed by flixos90.
Merges [57013] to the 6.4 branch.
Fixes #58962.