Make the test harness set the test product and application

If they are set in the tycho-surefire configuration in the pom.xml
file, then use this configuration when running SWTBot tests. This
allows test suites that use a non-default product (think CDT stand-
alone debugger) to run successfully.

Change-Id: I40c608ee4ebd5d3ac05976981bac49e4f996e819
Signed-off-by: Mat Booth <mat.booth@redhat.com>
Reviewed-on: https://git.eclipse.org/r/69984