RFR: 8229957: Harden pid verification in attach mechanism

[Severin Gehwolf]

On Wed, 2019-08-21 at 10:40 -0700, Leonid Mesnik wrote:
> Yasumasa, Severin
> 
> Thank you, I updated condition. Agree that pid might be equal 1 for java 
> in containers on linux and also might be for some specific configuration 
> with other OS. Se let just check that it is at least positive.
> 
> http://cr.openjdk.java.net/~lmesnik/8229957/webrev.01/

Looks good.

Thanks,
Severin