sql/tests: give more memory to TestSchemaChangesInParallel

The test has previously failed due to running out of memory. Since it's
an expensive test, this is somewhat expected.

Release note: None

pkg/sql/tests/schema_changes_in_parallel_test.go

@@ -39,6 +39,7 @@ func TestSchemaChangesInParallel(t *testing.T) {
 			},
 			JobsTestingKnobs: jobs.NewTestingKnobsWithShortIntervals(),
 		},
+		SQLMemoryPoolSize: 1 << 30, /* 1GiB */
 	})
 	defer s.Stopper().Stop(ctx)