Generalize sanitizer interceptors for memory and string routines
Similar to commit 3ead60236f ("Generalize bus_space(9) and atomic(9)
sanitizer interceptors"), use a more generic scheme for interposing
sanitizer implementations of routines like memcpy().
No functional change intended.
Sponsored by: The FreeBSD Foundation
(cherry picked from commit ec8f1ea8d536e91ad37e03e45a688c4e255b9cb0)