pgsql: Make platform guards in two regression tests match meson builds

Make platform guards in two regression tests match meson builds

collate.linux.utf8 skips itself unless version() matches "linux-gnu",
and infinite_recurse skips itself when version() matches
"powerpc64[^,]*-linux-gnu". configure substitutes the GNU host triplet
into that string, but the meson build composes it from
host_machine.cpu_family() and host_system, which never carries the ABI
suffix. So ever since meson support arrived in 16, collate.linux.utf8
has not run at all on a meson build, and infinite_recurse has been
running on ppc64 Linux the very case it means to stay away from.
Meson documentation says it reports 'ppc64' instead of 'powerpc64'.

Fix by matching "-linux[-,]" and "p(ower)?pc64[^,]*-linux", which match
all spellings. Keeping the punctuation on either side confines the
match to the platform field. Neither pattern excludes musl, but
collate.linux.utf8's other conditions already require a set of glibc
locales to be present.

Backpatch to 16, where the meson build was introduced.

Discussion: https://postgr.es/m/a40b19da-9a02-47b4-8afd-2bbbde8db1e8@dunslane.net

Reviewed-By: Jonathan Gonzalez V. <jonathan(at)abdiel(dot)eu>
Reviewed-By: Nazir Bilal Yavuz <byavuz81(at)gmail(dot)com>

Branch
------
REL_19_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/5523e4d9add7379398b5a998b83ddce3f64d72a4

Modified Files
--------------
src/test/regress/expected/collate.linux.utf8.out | 2 +-
src/test/regress/expected/collate.linux.utf8_1.out | 2 +-
src/test/regress/expected/infinite_recurse.out | 2 +-
src/test/regress/expected/infinite_recurse_1.out | 2 +-
src/test/regress/sql/collate.linux.utf8.sql | 2 +-
src/test/regress/sql/infinite_recurse.sql | 2 +-
6 files changed, 6 insertions(+), 6 deletions(-)