0.9.0.22: more fixed allocation

0.9.0.22: more fixed allocation
 * fix remaining WITH-FIXED-ALLOCATIONS with empty bodies. NB: there
    seems to be some doubt whether this is actually the right thing to
    do, as CMUCL has at least in sparc/float.lisp in MOVE-FOO-FLOAT a
    commit message by William Lott indicating that this was
    intentional "to avoid handling a trap within P-A". Which trap that
    would be is unclear, but hopefully we will eventually rediscover
    the cases where this is intentional.
 * make WITH-FIXED-ALLOCATION signal a BUG if body is empty to catch
    this in the future.
 * sprinkle WITH-FIXED-ALLOCATION with FAIRY-D^WONCE-ONLY on platforms
    that didn't have it yet.