hg: jdk/sandbox: 8198306: Add post custom extension hooks to two launchers

[chris.hegarty at oracle.com]

Changeset: 329428e095b6
Author:    erikj
Date:      2018-02-16 11:26 -0800
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/329428e095b6

8198306: Add post custom extension hooks to two launchers
Reviewed-by: erikj
Contributed-by: ben_walsh at uk.ibm.com

! make/launcher/Launcher-jdk.jcmd.gmk
! make/launcher/Launcher-jdk.jstatd.gmk