RFR: Add generations to freeset [v5]

[Kelvin Nilsen]

On Thu, 13 Apr 2023 11:12:05 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove debug instrumentation
>
> src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp line 559:
> 
>> 557:         assert(!is_mutator_free(idx) && !is_old_collector_free(idx), "Region cannot be in multiple free sets");
>> 558:         adjust_collector_bounds_if_touched(idx);
>> 559:       }
> 
> Do we ever get to generic `else` branch here? If not, we should assert that we are not expected to be there.

I've replaced the preceding "else if" with "else { assert()"

-------------

PR Review Comment: https://git.openjdk.org/shenandoah/pull/250#discussion_r1170581329