hg: jdk10/hs: 8169517: WhiteBox should provide concurrent GC phase control

[kim.barrett at oracle.com]

Changeset: cf738474cdb9
Author:    kbarrett
Date:      2017-04-13 16:39 -0400
URL:       http://hg.openjdk.java.net/jdk10/hs/rev/cf738474cdb9

8169517: WhiteBox should provide concurrent GC phase control
Summary: Added WhiteBox API and G1 implementation.
Reviewed-by: shade, dfazunen

! test/lib/sun/hotspot/WhiteBox.java