separation-logic-oriented versions of Balloc.v free_ok and alloc_ok
separation-logic-oriented versions of Balloc.v free_ok and alloc_ok

no proofs yet (just admit)

mit-pdos/fscq-impl,mit-pdos/fscq-impl,mit-pdos/fscq-impl,mit-pdos/fscq-impl,mit-pdos/fscq-impl