fix(ooapi): disable tests we're not using (ooni#525)

At the moment ooapi is not used. It will eventually be used since
it's a better way of accessing the OONI backend API.

To fix these tests, we need to fix the swagger emitted by the
backend API, which is not a priority at the moment, since we are
working instead to integrate websteps in miniooni.

Issue ooni/probe#1790 tracks the work
required to re-enabled the tests I'm skipping with this diff.

This work is part of ooni/probe#1733.

internal/ooapi/swaggerdiff_test.go

@@ -139,6 +139,7 @@ func compare(serverURL string) bool {
 }
 
 func TestWithProductionAPI(t *testing.T) {
+	t.Skip("skip until we use this part of the codebase")
 	if testing.Short() {
 		t.Skip("skip test in short mode")
 	}
@@ -149,6 +150,7 @@ func TestWithProductionAPI(t *testing.T) {
 }
 
 func TestWithTestingAPI(t *testing.T) {
+	t.Skip("skip until we use this part of the codebase")
 	if testing.Short() {
 		t.Skip("skip test in short mode")
 	}