[gc] fix the Coroutine GC bug #1108
[gc] fix the Coroutine GC bug #1108

 Coroutine.clone needs to reset the GC flags

youprofit/parrot,parrot/parrot,youprofit/parrot,youprofit/parrot,parrot/parrot,parrot/parrot,tkob/parrot,FROGGS/parrot,youprofit/parrot,tkob/parrot,tkob/parrot,tkob/parrot,youprofit/parrot,tkob/parrot,FROGGS/parrot,parrot/parrot,youprofit/parrot,FROGGS/parrot,tkob/parrot,youprofit/parrot,FROGGS/parrot,youprofit/parrot,tkob/parrot,parrot/parrot,FROGGS/parrot,FROGGS/parrot,tkob/parrot,FROGGS/parrot,FROGGS/parrot