Make Resources$DefaultTimeZones preloadable again.

Make Resources$DefaultTimeZones preloadable again.

http://s9/81864 was a premature optimization that stopped the timezone data
being loaded in the zygote. So instead of paying the (admittedly large) time
and space costs once in the zygote, we now pay them once per application.

Revert the problematic parts of that change. Note that this isn't simply a
reverse patch:

1. I've changed the comment to make it clear that although
this *looks* like idiomatic lazy initialization, it's actually the opposite.
A comment to that effect might have prevented this code from being broken.

2. I've left the last two hunks of the original patch stand, because they
appear reasonable but unrelated.

Bug: 1941311, 1819285.