pgsql: Fix concurrrently in typcache_rel_type_cache.sql

Fix concurrrently in typcache_rel_type_cache.sql

All injection points there must be local.  Otherwise it affects parallel
tests.

Reported-by: Andres Freund
Discussion: https://postgr.es/m/b3ybc66l6lhmtzj2n7ypumz5yjz7njc46sddsqshdtstgj74ah%40qgtn6nzokj6a

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/aa1e898dea666629bb5314fd25445545b9eb7b27

Modified Files
--------------
src/test/modules/typcache/expected/typcache_rel_type_cache.out | 7 +++++++
src/test/modules/typcache/sql/typcache_rel_type_cache.sql      | 3 +++
2 files changed, 10 insertions(+)