pgsql: spinlock emulation: Fix bug when more than INT_MAX spinlocks are

spinlock emulation: Fix bug when more than INT_MAX spinlocks are initialized.

Once the counter goes negative we ended up with spinlocks that errored
out on first use (due to check in tas_sema).

Author: Andres Freund
Reviewed-By: Robert Haas
Discussion: https://postgr.es/m/20200606023103.avzrctgv7476xj7i@alap3.anarazel.de
Backpatch: 9.5-

Branch
------
REL_12_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/b91cfaa34f44386786c64bbf80d296b84ecc811e

Modified Files
--------------
src/backend/storage/lmgr/spin.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)