pgsql: ci: Use a RAM disk for NetBSD and OpenBSD.

ci: Use a RAM disk for NetBSD and OpenBSD.

Put the RAM disk setup for all three *BSD CI tasks into a common script,
replacing the old FreeBSD-specific one from commit 0265e5c1. This makes
them run 3 times and a bit over 2 times faster, respectively.

NetBSD and FreeBSD now share the same one-liner to mount tmpfs. OpenBSD
needs a GCP-image specific recipe that knows where to steal an unused
disk partition needed to reserve swap space for an mfs RAM disk, because
its tmpfs is deprecated and currently broken. The configured size is
enough for our current tests but could potentially need future
expansion. Thanks to Bilal for the disklabel incantation.

Reviewed-by: Nazir Bilal Yavuz <byavuz81(at)gmail(dot)com>
Discussion: https://postgr.es/m/CA%2BhUKGJJ-XrPhN%2BQA4ZUfYAAXcwOSDty9t0vE9Z8__AdacKnQg%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b6904afae40d94c2f34bc3c94aee1cdbe0bcfbe9

Modified Files
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.cirrus.tasks.yml | 5 ++---
src/tools/ci/gcp_freebsd_repartition.sh | 26 --------------------------
src/tools/ci/gcp_ram_disk.sh | 22 ++++++++++++++++++++++
3 files changed, 24 insertions(+), 29 deletions(-)