Suppress complaints about leaks in function cache loading.

Suppress complaints about leaks in function cache loading.

PL/pgSQL and SQL-function parsing leak some stuff into the long-lived
function cache context.  This isn't really a huge practical problem,
since it's not a large amount of data and the cruft will be recovered
if we have to re-parse the function.  It's not clear that it's worth
working any harder than the previous patch did to eliminate these
leak complaints, so instead silence them with a suppression rule.

This suppression rule also hides the fact that CachedFunction structs
are intentionally leaked in some cases because we're unsure if any
fn_extra pointers remain.  That might be nice to do something about
eventually, but it's not clear how.

Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/285483.1746756246@sss.pgh.pa.us