1.0.29.34: hopefully thread-safe SB-PROFILE

1.0.29.34: hopefully thread-safe SB-PROFILE

* Nuke PCOUNTER stuff, and replace it with a COUNTER local to
  profile.lisp:

  ** New counter uses ATOMIC-INCF for atomicity, plus a lock and
     an overflow counter to handle counts over word in size.

  ** Stack allocate counters and counter value cells when possible
     to reduce overhead.

* Nuke the FASTBIG-stuff. A generic arithmetic call with fixnum args
  is not that slow -- and if it turns out to be too slow after all,
  then the compiler should take care of this under appropriate policy
  instead of us using hacks like this.

* Test case from Volkan Yazici.