Fix a panic call, so we actually panic with the useful error message.
Fix a panic call, so we actually panic with the useful error message.

cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,cygx/nqp,perl6/nqp-rx,cygx/nqp,cygx/nqp,cygx/nqp,perl6/nqp-rx