Instrument call to sealContract in end to end tests

[dorranh]

The call to sealContract is not currently instrumented in our tests, which means that we won't see reports of its gas costs. We should add support for this in our end to end tests.

[gkaracha]

Ah, yes, indeed! Expect this to be the most expensive of all though, since internally it calls touch and pokes all helper contracts 😅