hg: jdk/jdk12: 8215548: G1PeriodicGCSystemLoadThreshold needs to be a double

[thomas.schatzl at oracle.com]

Changeset: 759266b1c89b
Author:    tschatzl
Date:      2018-12-20 19:44 +0100
URL:       http://hg.openjdk.java.net/jdk/jdk12/rev/759266b1c89b

8215548: G1PeriodicGCSystemLoadThreshold needs to be a double
Summary: Change G1PeriodicGCSystemLoadThreshold to be a double to allow better granularity in determining idleness
Reviewed-by: sjohanss, sangheki

! src/hotspot/share/gc/g1/g1YoungRemSetSamplingThread.cpp
! src/hotspot/share/gc/g1/g1_globals.hpp