pgsql: Lock table in DROP STATISTICS

Lock table in DROP STATISTICS

The DROP STATISTICS code failed to properly lock the table, leading to

  ERROR:  tuple concurrently deleted

when executed concurrently with ANALYZE.

Fixed by modifying RemoveStatisticsById() to acquire the same lock as
ANALYZE. This function is called only by DROP STATISTICS, as ANALYZE
calls RemoveStatisticsDataById() directly.

Reported by Justin Pryzby, fix by me. Backpatch through 12. The code was
like this since it was introduced in 10, but older releases are EOL.

Reported-by: Justin Pryzby
Reviewed-by: Tom Lane
Backpatch-through: 12

Discussion: https://postgr.es/m/ZUuk-8CfbYeq6g_u@pryzbyj2023

Branch
------
REL_14_STABLE

Details
-------
https://git.postgresql.org/pg/commitdiff/9dd50e92ed239bc4643c1df7e9e0bcc03b05bfef

Modified Files
--------------
src/backend/commands/statscmds.c | 39 +++++++++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 10 deletions(-)