firefox: enable in i686

[Chocimier]

Have the results of the proposed changes been tested?

• I use the packages affected by the proposed changes on a regular basis and confirm this PR works for me
• I generally don't use the affected packages (on i686) but briefly tested this PR

Does it build and run successfully?

• I built this PR locally for my native architecture, i686

references #30031

[ci skip]

[ericonr]

Is the OOM non deterministic, then? We had it fail a lot of times on builders :/

[Chocimier]

87 was failing for me too, recent update to 88 passed on first try.

[ericonr]

Ah, nice!