Consolidate Dolt-specific foreign key tests into `dolt_queries_foreign_keys.go`

Several tests that belong to the file are scattered in `dolt_queries.go`. This is a part of the process of debloating `dolt_queries.go` and organizing of test infrastructure. `dolt_queries_foreign_keys.go` was added in dolthub/dolt#10906 to house Dolt-specific foreign key tests separately from the engine-level tests in `go-mysql-server`.

Start by comparing dolt_queries.go with dolt_queries_foreign_keys.go and identify the Dolt-specific foreign key tests still in the former. Move those tests into the dedicated file while keeping engine-level tests separate. Run the relevant Go test suite and confirm the tests remain passing and dolt_queries.go is debloated.

Written by the indexing model from the issue text.