overlayworkginctx: implement a setparents() to mirror dirstate.setparents()...
overlayworkginctx: implement a setparents() to mirror dirstate.setparents()
This lets us make the in-memory and on-disk code a bit more
similar. I'll soon also implement setparents() on the regular
workingctx.
Differential Revision:
https://phab.mercurial-scm.org/D7822