RFR 8214442: Improve stack walk API by adding handle marks

[zgu at redhat.com]

Looks good to me.

Thanks,

-Zhengyu

On Tue, 2019-01-08 at 09:17 -0500, Harold David Seigel wrote:
> Hi,
> 
> Please review this small JDK-13 change to add handle marks to the
> stack 
> walk API for reasons described in the bug.
> 
> Open Webrev: 
> http://cr.openjdk.java.net/~hseigel/bug_8214442/webrev/index.html
> 
> JBS Bug:  https://bugs.openjdk.java.net/browse/JDK-8214442
> 
> The fix was regression tested by running Mach5 tiers 1 and 2 tests
> and 
> builds on Linux-x64, Windows, and Mac OS X, Mach5 tiers 3 -5 o 
> Linux-x64, and by running JCK-12 Lang and VM tests on Linux-x64.
> 
> Thanks, Harold
>