RFR: 8234773: Fix ThreadsSMRSupport::_bootstrap_list [v2]

[Kim Barrett]

> On Jan 5, 2021, at 4:12 PM, Daniel D.Daugherty <dcubed at openjdk.java.net> wrote:
> 
> On Mon, 4 Jan 2021 12:19:14 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:
> 
>>> Please review this change to ThreadsList and the singleton _bootstrap_list.
>>> […]
>> 
>> Kim Barrett has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>  Make ThreadsList constructor explicit.
> 
> Thumbs up.
> Like @dholmes-ora, I'm not familiar with this "explicit" stuff.

Thanks.

> Marked as reviewed by dcubed (Reviewer).
> 
> PR: https://git.openjdk.java.net/jdk/pull/1921