pgsql: Simplify checks for deterministic collations.

Simplify checks for deterministic collations.

Remove redundant checks for locale->collate_is_c now that we always
have a valid pg_locale_t.

Also, remove pg_locale_deterministic() wrapper, which is no longer
useful after commit e9931bfb75. Just check the field directly,
consistent with other fields in pg_locale_t.

Author: Andreas Karlsson
Discussion: https://postgr.es/m/60929555-4709-40a7-b136-bcb44cff5a3c@proxel.se

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/b0c30612c5f6ce519172396527781a0666937363

Modified Files
--------------
src/backend/access/hash/hashfunc.c | 4 ++--
src/backend/regex/regc_pg_locale.c | 2 +-
src/backend/utils/adt/like.c | 4 ++--
src/backend/utils/adt/pg_locale.c | 7 -------
src/backend/utils/adt/varchar.c | 8 ++++----
src/backend/utils/adt/varlena.c | 18 +++++++-----------
src/include/utils/pg_locale.h | 1 -
7 files changed, 16 insertions(+), 28 deletions(-)