In 9.0+, featureFlagExtensionsAPI is enabled by default, so the stub parser
// throws 10918500 ("extension is not available") when the extension is not loaded.
// On backports, it throws 40324 ("unrecognized stage").
const fooStageUnrecognizedErrCodes = [40324, 10918500];

...
// Either outcome is acceptable in this mixed-version state.
    assert.commandWorkedOrFailedWithCode(
        db.createView(viewName, collName, [{$testFoo: {}}]),
        fooStageUnrecognizedErrCodes);