RFR (S) 8211926: Catastrophic size_t underflow in BitMap::*_large methods

[Kim Barrett]

> On Nov 9, 2018, at 6:31 PM, Aleksey Shipilev <shade at redhat.com> wrote:
> 
> On 11/09/2018 09:02 PM, Kim Barrett wrote:
>> Almost, but not quite, I'm afraid.  All but the first comment below
>> are optional, though I think make things better.
> 
> Introduced helper method, moved the small_range_words to private, handled (l == r) corner case in
> test. See:
>  http://cr.openjdk.java.net/~shade/8211926/webrev.05/

Looks good.