Add support for pg_get_serial_sequence(text,text)

[fulghum]

Adds support for the pg_get_serial_sequence(text,text) function, which returns the sequence owned by a column.

Example usage:

create table t1 (id SERIAL PRIMARY KEY);
SELECT pg_get_serial_sequence('t1', 'id');

[github-actions]

	Main	PR
Total	42090	42090
Successful	15344	15344
Failures	26746	26746
Partial Successes1	5232	5232

	Main	PR
Successful	36.4552%	36.4552%
Failures	63.5448%	63.5448%

Footnotes

1. These are tests that we're marking as Successful, however they do not match the expected output in some way. This is due to small differences, such as different wording on the error messages, or the column names being incorrect while the data itself is correct. ↩

[github-actions]

	Main	PR
covering_index_scan_postgres	361.56/s	371.71/s	+2.8%
index_join_postgres	153.18/s	155.06/s	+1.2%
index_join_scan_postgres	182.03/s	185.89/s	+2.1%
index_scan_postgres	12.63/s	12.67/s	+0.3%
oltp_point_select	2792.46/s	2820.72/s	+1.0%
oltp_read_only	1880.81/s	1884.55/s	+0.1%
select_random_points	113.04/s	113.26/s	+0.1%
select_random_ranges	130.66/s	129.58/s	-0.9%
table_scan_postgres	11.85/s	12.01/s	+1.3%
types_table_scan_postgres	5.66/s	5.67/s	+0.1%

[Hydrocharged]

LGTM!