pgsql: ci: Use VMs for SanityCheck and CompilerWarnings

ci: Use VMs for SanityCheck and CompilerWarnings

The main reason for this change is to reduce different ways of executing
tasks, making it easier to use custom compute resources for cfbot. A secondary
benefit is that the tasks seem slightly faster this way, apparently the
increased startup overhead is outweighed by reduced runtime overhead.

Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/20230808021541.7lbzdefvma7qmn3w@awork3.anarazel.de
Backpatch: 15-, where CI support was added

Branch
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REL_15_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/4fdfd0629d77af19582ca4d59c0e7fe99619f048

Modified Files
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.cirrus.yml | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)