chore: remove references to dbtestutil.WillUsePostgres (#20436)

Addresses https://github.com/coder/internal/issues/758.

This PR only cleans up dead code, it makes no changes to test logic.

enterprise/coderd/coderd_test.go

@@ -79,10 +79,6 @@ func TestEntitlements(t *testing.T) {
 		require.Equal(t, fmt.Sprintf("%p", api.Entitlements), fmt.Sprintf("%p", api.AGPL.Entitlements))
 	})
 	t.Run("FullLicense", func(t *testing.T) {
-		// PGCoordinator requires a real postgres
-		if !dbtestutil.WillUsePostgres() {
-			t.Skip("test only with postgres")
-		}
 		t.Parallel()
 		adminClient, _ := coderdenttest.New(t, &coderdenttest.Options{
 			AuditLogging:   true,
@@ -882,10 +878,6 @@ func (s *restartableTestServer) startWithFirstUser(t *testing.T) (client *coders
 func TestConn_CoordinatorRollingRestart(t *testing.T) {
 	t.Parallel()
 
-	if !dbtestutil.WillUsePostgres() {
-		t.Skip("test only with postgres")
-	}
-
 	// Although DERP will have connection issues until the connection is
 	// reestablished, any open connections should be maintained.
 	//