[8u] Request for Backport approval for JDK-8184309: Fix build warnings from gcc 7.x

[Siddhesh Poyarekar]

Hello,

I would like to request approval to backport the patch that fixed build 
warnings flagged by gcc 7.x.  The bug report is below and was fixed in 
jdk10:

https://bugs.openjdk.java.net/browse/JDK-8184309

The jdk10 fix is here:

http://hg.openjdk.java.net/jdk10/jdk10/hotspot/rev/eb11b3f0ae65

The minimal applicable fix for jdk8u is below:

https://mail.openjdk.java.net/pipermail/jdk8u-dev/2018-December/008341.html

This was reviewed by Andrew Hughes and he has implemented a similar fix 
himself but didn't get to upstreaming it yet:

https://mail.openjdk.java.net/pipermail/jdk8u-dev/2019-January/008352.html

Thanks,
Siddhesh