hg: jdk9/dev/jdk: 8171374: GenGraphs should filter the rank grouping if the group is empty

[mandy.chung at oracle.com]

Changeset: a3539d97b127
Author:    mchung
Date:      2016-12-16 09:42 -0800
URL:       http://hg.openjdk.java.net/jdk9/dev/jdk/rev/a3539d97b127

8171374: GenGraphs should filter the rank grouping if the group is empty
Reviewed-by: alanb, psandoz

! make/src/classes/build/tools/jigsaw/GenGraphs.java