RE: speed up a logical replica setup

Dear Euler,

Here are my minor comments for 17.

01.
```
/* Options */
static const char *progname;

static char *primary_slot_name = NULL;
static bool dry_run = false;

static bool success = false;

static LogicalRepInfo *dbinfo;
static int num_dbs = 0;
```

The comment seems out-of-date. There is only one option.

02. check_subscriber and check_publisher

Missing pg_catalog prefix in some lines.

03. get_base_conninfo

I think dbname would not be set. IIUC, dbname should be a pointer of the pointer.

04.

I check the coverage and found two functions have been never called:
- drop_subscription
- drop_replication_slot

Also, some cases were not tested. Below bullet showed notable ones for me.
(Some of them would not be needed based on discussions)

* -r is specified
* -t is specified
* -P option contains dbname
* -d is not specified
* GUC settings are wrong
* primary_slot_name is specified on the standby
* standby server is not working

In feature level, we may able to check the server log is surely removed in case
of success.

So, which tests should be added? drop_subscription() is called only when the
cleanup phase, so it may be difficult to test. According to others, it seems that
-r and -t are not tested. GUC-settings have many test cases so not sure they
should be. Based on this, others can be tested.

PSA my top-up patch set.

V18-0001: same as your patch, v17-0001.
V18-0002: modify the alignment of codes.
V18-0003: change an argument of get_base_conninfo. Per comment 3.
=== experimental patches ===
V18-0004: Add testcases per comment 4.
V18-0005: Remove -P option. I'm not sure it should be needed, but I made just in case.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED
https://www.fujitsu.com/global/