hg: shenandoah/jdk: Set ShenandoahMinFreeThreshold default to 10%

[ashipile at redhat.com]

Changeset: f487f6cde0e6
Author:    shade
Date:      2018-05-03 11:05 +0200
URL:       http://hg.openjdk.java.net/shenandoah/jdk/rev/f487f6cde0e6

Set ShenandoahMinFreeThreshold default to 10%

! src/hotspot/share/gc/shenandoah/shenandoah_globals.hpp