Fully outline all GlobalRefs (#56746)
This is an alternative to #56714 that goes in the opposite direction -
just outline all GlobalRefs during lowering. It is a lot simpler that
#56714 at the cost of some size increase. Numbers:
sys.so .ldata size:
This PR: 159.8 MB
Master: 158.9 MB
I don't have numbers of #56714, because it's not fully complete.
Additionally, it's possible that restricting GlobalRefs from arguments
position would let us use a more efficient encoding in the future.
