Partially revert "Disable localisation when SOURCE_DATE_EPOCH is set (#10949)"

[AA-Turner]

Alternative to @jayaddison's #11306.

The comment at #9778 (comment) posits that the reproducability issue is already fixed, but the objects.inv reproducability test is failing -- @jayaddison any suggestions?

A

[jayaddison]

@AA-Turner I think that I miswrote the test, based on incorrect assumptions.

It says: the EN and ET inventories should be identical in a reproducible build, but what that means is: check that localisation is disabled.

That's not a viable fix, in my opinion. Ideally we want localisation to continue to be supported: we can't rule-out the system build locale as a variance factor in the output until there is a way to configure and build for multiple locales (essentially: ignore the system build locale, and build for all/a configured list of locales, producing identical results each time).

In short: I don't feel comfortable disabling localisation in reproducible-builds builds entirely - it seems like the wrong approach.

[jayaddison]

Thanks @AA-Turner!