Make GIN tests using injection points concurrent-safe
f587338dec87 has introduced in the test module injection_points a SQL
function called injection_points_set_local(), that can be used to make
all the injection points linked to the process where they are attached,
discarded automatically if any remain once the process exits.
e2e3b8ae9ed7 has added a NO_INSTALLCHECK to the test module to prevent
the use of installcheck. Now that there is a way to make the test
concurrent-safe, let's use it and remove the installcheck restriction.
Concurrency issues could be easily reproduced by running in a tight
loop a command like this one, in src/test/modules/gin/ (hardcoding
pg_sleep() after attaching injection points enlarges the race window)
and a second test suite like contrib/btree_gin/:
make installcheck USE_MODULE_DB=1
Reviewed-by: Andrey Borodin
Discussion: https://postgr.es/m/ZhNG4Io9uYOgwv3F@paquier.xyz