RFR(S): 8155241: Crash with assert in Xcomp mode and with disabled ReduceBulkZeroing

[Roland Westrelin]

> Yes, I think the assert is wrong because it assumes that a clonebasic
> arraycopy always takes care of zeroing (simply by overwriting) a
> newly allocated destination array. However, with
> -XX:-ReduceBulkZeroing this is not the case and the array is
> needlessly zeroed directly after the allocation and before the
> clonebasic which overwrites the array anyway.
> 
> Maybe Roland (CC'ed) can verify.

I don't remember for sure but AFAICT, the assert is only a sanity check
so I would say the change is good.

Roland.