Improve correlation names in sanity tests

Improve correlation names in sanity tests

Some of the queries in the "sanity" tests in the regression test suite
(opr_sanity, type_sanity) are very confusing.  One main stumbling
block is that for some probably ancient reason many of the older
queries are written with correlation names p1, p2, etc. independent of
the name of the catalog. This one is a good example:

SELECT p1.oid, p1.oprname, p2.oid, p2.proname
FROM pg_operator AS p1, pg_proc AS p2          <-- HERE
WHERE p1.oprcode = p2.oid AND
    p1.oprkind = 'l' AND
    (p2.pronargs != 1
     OR NOT binary_coercible(p2.prorettype, p1.oprresult)
     OR NOT binary_coercible(p1.oprright, p2.proargtypes[0])
     OR p1.oprleft != 0);

This is better written as

SELECT o1.oid, o1.oprname, p1.oid, p1.proname
FROM pg_operator AS o1, pg_proc AS p1
WHERE o1.oprcode = p1.oid AND
    o1.oprkind = 'l' AND
    (p1.pronargs != 1
     OR NOT binary_coercible(p1.prorettype, o1.oprresult)
     OR NOT binary_coercible(o1.oprright, p1.proargtypes[0])
     OR o1.oprleft != 0);

This patch cleans up all the queries in this manner.

(As in the above case, I kept the digits like o1 and p1 even in cases
where only one of each letter is used in a query.  This is mainly to
keep the style consistent.)

Discussion: https://www.postgresql.org/message-id/flat/c538308b-319c-8784-e250-1284d12d5411%40enterprisedb.com