Harmonize some more function parameter names.

Harmonize some more function parameter names.

Make sure that function declarations use names that exactly match the
corresponding names from function definitions in a few places.  These
inconsistencies were all introduced relatively recently, after the code
base had parameter name mismatches fixed in bulk (see commits starting
with commits 4274dc22 and 035ce1fe).

pg_bsd_indent still has a couple of similar inconsistencies, which I
(pgeoghegan) have left untouched for now.

Like all earlier commits that cleaned up function parameter names, this
commit was written with help from clang-tidy.