hg: jmc/jmc: JMC-6274: Fix PluginTest uitest failure after 2019-03 target platform addition

[jmatsuok at redhat.com]

Changeset: 2ecf88bb5f34
Author:    aptmac <almacdon at redhat.com>
Date:      2019-05-02 08:56 -0400
URL:       http://hg.openjdk.java.net/jmc/jmc/rev/2ecf88bb5f34

JMC-6274: Fix PluginTest uitest failure after 2019-03 target platform addition
Summary: Platform UI introduced a change in the Installation Dialog to use CTabFolder instead of TabFolder. This caused a NPE when Jemmy tried to retrieve a TabFolder for testing.
Reviewed-by: hirt

! application/uitests/org.openjdk.jmc.test.jemmy/src/test/java/org/openjdk/jmc/test/jemmy/misc/wrappers/MCInstallation.java