additional tests for merging foreign keys and constraint violations

[zachmu]

No description provided.

[github-actions]

	Main	PR
covering_index_scan_postgres	570.60/s	568.49/s	-0.4%
index_join_postgres	122.78/s	124.15/s	+1.1%
index_join_scan_postgres	183.24/s	183.92/s	+0.3%
index_scan_postgres	11.32/s	11.33/s	0.0%
oltp_point_select	2341.20/s	2389.38/s	+2.0%
oltp_read_only	1690.40/s	1716.90/s	+1.5%
select_random_points	110.70/s	110.44/s	-0.3%
select_random_ranges	433.77/s	429.55/s	-1.0%
table_scan_postgres	11.17/s	11.09/s	-0.8%
types_table_scan_postgres	5.19/s	5.08/s	-2.2%

[github-actions]

	Main	PR
Total	42090	42090
Successful	17565	17565
Failures	24525	24525
Partial Successes1	5583	5583

	Main	PR
Successful	41.7320%	41.7320%
Failures	58.2680%	58.2680%

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!