Continue working to make GlobalRef more first-class
The `owner` field now points directly at the target binding (which may
be itself), rather than indirecting through a module+name re-lookup.
This makes `module X; import .x as y; end` behavior more precise.
The `globalref` field is currently now mandatory, since otherwise
incremental compilation will be impossible right now. Maybe world-age
splitting will help improve that later?
Fix up a lot of locations that previously used the `name` field badly.
There are some valid uses of this, but mostly it was wrong, since it
would may fail to reflect what content actually appeared in the user's
code. Directly forwarding the actual lookup result is cleaner and
clearer for the user in most cases.
Also remove `resolve` for GlobalRef:
This has been wrong since `import as` was added, and appears unused and untested.
