RFR: 8203843: BasicParState::default_estimated_thread_count(false) can return 0 in gtest

[Kim Barrett]

> On May 29, 2018, at 4:39 AM, Robbin Ehn <robbin.ehn at oracle.com> wrote:
> 
> Thanks for addressing this so quickly, looks good!
> 
> /Robbin

Thanks.

> 
> On 05/28/2018 10:14 PM, Kim Barrett wrote:
>> Please review this small change to default_estimated_thread_count to
>> always return a value of at least 1.
>> CR:
>> https://bugs.openjdk.java.net/browse/JDK-8203843
>> Webrev:
>> http://cr.openjdk.java.net/~kbarrett/8203843/open.00/