pgsql: Replace get_equal_strategy_number_for_am() by get_equal_strategy

Replace get_equal_strategy_number_for_am() by get_equal_strategy_number()

get_equal_strategy_number_for_am() gets the equal strategy number for
an AM.  This currently only supports btree and hash.  In the more
general case, this also depends on the operator class (see for example
GistTranslateStratnum()).  To support that, replace this function with
get_equal_strategy_number() that takes an opclass and derives it from
there.  (This function already existed before as a static function, so
the signature is kept for simplicity.)

This patch is only a refactoring, it doesn't add support for other
index AMs such as gist.  This will be done separately.

Reviewed-by: Paul Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: vignesh C <vignesh21@gmail.com>
Discussion:
https://www.postgresql.org/message-id/flat/CA+renyUApHgSZF9-nd-a0+OPGharLQLO=mDHcY4_qQ0+noCUVg@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a2a475b011cf7c25f5a09574def35b335af844ac

Modified Files
--------------
src/backend/executor/execReplication.c     | 17 +++--------------
src/backend/replication/logical/relation.c | 19 ++++++++++++++-----
src/include/executor/executor.h            |  2 +-
3 files changed, 18 insertions(+), 20 deletions(-)