Fix for reset_context() so that the top two stack items are never
removed from the stack so if the parent->init_context(ctx) call triggers
a GC, those items are never collected.
simplified a bit
The functions always operates on parent->ctx, so passing a context*
parameter is redundant. This enables shorter assembly code for
the (start-context-and-delete) and (set-context-and-delete) primitives.
All the bootstrap.factor scripts in cpu/ are run by the bootstrap to
make boot images, but aren't used otherwise. So I think it's cleaner to
put them in one directory inside the bootstrap hierarchy.
Björn Lindqvist