dc728b3895 introduced some non-determinism
by mutating the global TARGETS list.
The result is, depending on iteration order, the generated jobs
may inherit the env from earlier jobs.
Notably, if the tag job inherit the schedule reason from a continuous
job, they'll upload assets with an incorrect filename.
This commit restores the determinism by forcing each iteration
of the generation loop to make a deep copy of the statically
defined information in TARGETS.
While we're at it, ensure that the list of env vars is sorted
to avoid non-determinism there as well.
refs: https://github.com/wez/wezterm/issues/2176
ce89e33f01