workload/schemachange: add fk constraints and type improvements

[jayshrivastava]

workload/schemachange: implement addForeignKeyConstraint op

addForeignKeyConstraint adds a single, non-composite, foreign key relation
between two random columns.

Closes: #57472
Release note: None

workload/schemachange: implement addUniqueConstraint op

The addUniqueConstraint op adds a unique constraint on a single
column.

Release note: None

workload/schemachange: add oid type resolution to type resolver

Previously, the workload was failing because, in certain situations,
it would expect certain type errors and they would not occur. This was due
to the type resolver incorrectly resolving non user-defined types as enums.
This change adds some logic to properly resolve non user-defined types
by OID.

Closes: #57993
Release note: None

workload/schemachange: expect undefined table in create sequence

Previously, creating a sequence that was owned by a column
from a non existing table would cause an unexpected
pgcode.UndefinedTable. This change ensures that this error
is expected when the table does not exist.
Release note: None

[cockroach-teamcity]

This change is 

[ajwerner]

Reviewed 4 of 4 files at r1, 2 of 2 files at r2, 1 of 1 files at r3, 1 of 1 files at r4.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @jayshrivastava)

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pkg/workload/schemachange/error_screening.go, line 586 at r1 (raw file):

}

func violatesFkConstraintsHelper(

This could use a better name and a comment.

---

pkg/workload/schemachange/operation_generator.go, line 321 at r1 (raw file):

func (og *operationGenerator) addForeignKeyConstraint(tx *pgx.Tx) (string, error) {

	// Use og.produceError() to determine if errors will be produced due to the column being generated

Is this comment stale?

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pkg/workload/schemachange/type_resolver.go, line 36 at r3 (raw file):

) (*types.T, error) {

	// An explicit schema indicates the type is a user defined enum type.

that's subtle and doesn't need to be the case. Comment on this function if you're going with that.

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pkg/workload/schemachange/type_resolver.go, line 44 at r3 (raw file):

         AND typcategory = 'E'
         AND typname = $1
				 AND nspname = $2

nit: weird indentation

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pkg/workload/schemachange/type_resolver.go, line 46 at r3 (raw file):

				 AND nspname = $2
ORDER BY enumsortorder`, name.Object(), name.Schema())
		fmt.Println(err, "ASDFASDF")

remove

[jayshrivastava]

bors r=ajwerner

[craig]

Build succeeded:

• GitHub CI (Cockroach)