Fix #6061 : Revert commits to fix bootstrapping issue 6061

I have confirmed that reverting these two commits gets me bootstrapping again (or rather, my build finishes without erroring out during the first 1/3 of the build).

I don't know yet why these changes exposed this problem; obviously that requires investigation.  But I figured it was best to try to get the build working again (and also to advertise this revert to other people who have been encountering similar problems according to the #rust channel and find out if it fixes things for them too -- so even if this pull request doesn't land, I figure I should issue it just as advertisement.)