additional tests for merging foreign keys and constraint violations

[zachmu]

No description provided.

[github-actions]

	Main	PR
covering_index_scan_postgres	564.97/s	566.23/s	+0.2%
index_join_postgres	119.15/s	119.79/s	+0.5%
index_join_scan_postgres	176.08/s	177.31/s	+0.6%
index_scan_postgres	11.12/s	11.27/s	+1.3%
oltp_point_select	2314.89/s	2300.51/s	-0.7%
oltp_read_only	1702.85/s	1680.09/s	-1.4%
select_random_points	105.42/s	106.85/s	+1.3%
select_random_ranges	423.27/s	428.51/s	+1.2%
table_scan_postgres	10.84/s	10.87/s	+0.2%
types_table_scan_postgres	4.97/s	5.03/s	+1.2%

[github-actions]

	Main	PR
Total	42090	42090
Successful	17563	17563
Failures	24527	24527
Partial Successes1	5582	5582

	Main	PR
Successful	41.7273%	41.7273%
Failures	58.2727%	58.2727%

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. ↩

[Hydrocharged]

LGTM!

[Hydrocharged]

I do like adding results checking for these. We used to skip because we didn't yet support their output, but that was fixed quite a while ago.

[Hydrocharged]

For dolt_merge we'd do something like:

{
	Query:    "select strpos(dolt_merge('main')::text, 'merge successful') > 1;",
	Expected: []sql.Row{{"t"}},
},