RFR: 8202353: os::readdir should use readdir instead of readdir_r

[Kim Barrett]

> On Jul 10, 2018, at 4:18 PM, Kim Barrett <kim.barrett at oracle.com> wrote:
> 
> Please review this change to the various os::readdir implementations
> for POSIX platforms to no longer use readdir_r, but instead use
> readdir.  […]
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8202353
> https://bugs.openjdk.java.net/browse/JDK-8202835
> 
> Webrev:
> http://cr.openjdk.java.net/~kbarrett/8202353/open.00/
> 
> Testing:
> mach5 tier1-5.
> tier5 is where TestSystemProcess.java is run.
> There are a number of jfr tests in tier3-4 that use process iterators on
> relevant platforms.
> There are tests related to PerfCounters scattered through tier1-3.

Still looking for at least one more review.  I have one from Coleen, and a partial from Bernard.