Harmonize parameter names in pg_dump/pg_dumpall.

Harmonize parameter names in pg_dump/pg_dumpall.

Make sure that function declarations use names that exactly match the
corresponding names from function definitions in pg_dump/pg_dumpall
related code.

Affected code happens to be inconsistent in how it applies conventions
around how Archive and Archive Handle variables are named.  Significant
code churn is required to fully fix those inconsistencies, so take the
least invasive approach possible: treat function definition names as
authoritative, and mechanically adjust corresponding names from function
definitions to match.

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

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAH2-Wzmma+vzcO6gr5NYDZ+sx0G14aU-UrzFutT2FoRaisVCUQ@mail.gmail.com