GC [Trampolines]: Reenable the gc callbacks.
gc_recurse_frame() now uses visit_ref().
GC [Trampolines]: Disable gc_check_frame() too.
This is needed to make the gc happy.
Fixes fatal: Using unmarked freed svalue.
GC [Trampolines]: Disable gc_recurse_frame() for now.
gc_recurse_frame() is seriously broken for the case where
the same frame is referred to from several objects. This
leads to the references from the frame being counted once
for every reference to the frame.