April patch set for TenFourFox

I've had my hands full with the POWER9 64-bit JIT (a descendant of TenFourFox's 32-bit JIT), but I had a better idea about the lazy image loader workaround in February's drop and got the rest of the maintenance patches down at the same time. These patches include the standard security fixes and updates to timezones, pinned certificates and HSTS, as well as another entry for the ATSUI font blacklist. In addition, a bug in the POWER9 JIT turns out to affect TenFourFox as well (going back to at least TenFourFox 38), which I ported a fix for. It should correct some residual issues with IonPower-NVLE on a few sites, though it may allow code to run that couldn't run before that may have its own issues, of course. A clobber is not required for this update. The commits are already hot and live on Github.

The next ESR, version 102, is due in June. I'll change the EV and certificate roots over around that time as usual, but we might also take the opportunity to pull up some of the vendored libraries like zlib, so it might be a somewhat bigger update than it would ordinarily be.