bpart: Start tracking backedges for bindings (#57213)
This PR adds limited backedge support for Bindings. There are two
classes of bindings that get backedges:
1. Cross-module `GlobalRef` bindings (new in this PR)
2. Any globals accesses through intrinsics (i.e. those with forward
edges from #57009)
This is a time/space trade-off for invalidation. As a result of the
first category, invalidating a binding now only needs to scan all the
methods defined in the same module as the binding. At the same time, it
is anticipated that most binding references are to bindings in the same
module, keeping the list of bindings that need explicit (back)edges
small.
