[parrot/parrot] 18c6a7: [gc] fix crash when allocate_registers causes a GC

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/parrot/parrot
  Commit: 18c6a705d620a437f448738a05839378ad24ea19
      https://github.com/parrot/parrot/commit/18c6a705d620a437f448738a05839378ad24ea19
  Author: Reini Urban <rurban at cpanel.net>
  Date:   2014-11-17 (Mon, 17 Nov 2014)

  Changed paths:
    M src/pmc/callcontext.pmc

  Log Message:
  -----------
  [gc] fix crash when allocate_registers causes a GC

then CallContext->bp_ps is still zeroed, and CallContext.mark must
not access them.

Repro: ./parrot --gc ms2 examples/benchmarks/oofib.pir
(recursive calls)