hg: jdk9/dev/jdk: 8132500: Add imageio test to tier 3

[joe.darcy at oracle.com]

Changeset: 29634bb4e3ac
Author:    darcy
Date:      2015-07-31 16:03 -0700
URL:       http://hg.openjdk.java.net/jdk9/dev/jdk/rev/29634bb4e3ac

8132500: Add imageio test to tier 3
Reviewed-by: prr

! test/TEST.groups