Order getopt arguments

Order getopt arguments

Order the letters in the arguments of getopt() and getopt_long(), as
well as in the subsequent switch statements.  In most cases, I used
alphabetical with lower case first.  In a few cases, existing
different orders (e.g., upper case first) was kept to reduce the diff
size.

Discussion: https://www.postgresql.org/message-id/flat/3efd0fe8-351b-f836-9122-886002602357%40enterprisedb.com