Add conditional execution to batch specs

Created by: mrnugget

This is a sub-ticket of https://github.com/sourcegraph/sourcegraph/issues/19476 and created retroactively after I added conditional execution in https://github.com/sourcegraph/src-cli/pull/520, https://github.com/sourcegraph/sourcegraph/pull/20701, https://github.com/sourcegraph/sourcegraph/pull/20399.

This is just here to track the progress.