Tezos job timeout

[Sudha247]

Currently (on commit f5d080c) a job's timeout is set to 7 hours. The Tezos job on 4.12.0+domains occasionally surpasses this time limit resulting in a failed job. (cf. https://multicore.ci.ocamllabs.io:8100/job/2021-12-12/233831-ci-ocluster-build-effa23)

While 7 hours is a reasonably lengthy time limit, we should also take into consideration that the python integration tests that are part of Tezos' test suite in itself take close to 4 hours. Before attempting other means, it might be useful to increase the time limit to see if that results in completing the test-suite run.

cc @moyodiallo