[rfc] Running unmodified AArch32 Linux programs on Fuchsia

This RFC enables running of unmodified, untrusted AArch32 guest code via
restricted mode and starnix.

Bug: 388011178
Change-Id: I5e0be96288be39a5ede87d138d46bbd6e8187b47
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1151293
Reviewed-by: Travis Geiselbrecht <travisg@google.com>
Reviewed-by: Hunter Freyer <hjfreyer@google.com>
Reviewed-by: Kevin Lindkvist <lindkvist@google.com>
Reviewed-by: Marco Vanotti <mvanotti@google.com>
Reviewed-by: Roland McGrath <mcgrathr@google.com>
Reviewed-by: Petr Hosek <phosek@google.com>
Commit-Queue: Will Drewry <drewry@google.com>
Reviewed-by: James Robinson <jamesr@google.com>
Reviewed-by: Nick Maniscalco <maniscalco@google.com>