Bug 454544: Add a emptyHashMap() method to CollectionUtility.
Add unittest for emptyHashMap(), emptyHashSet() and emptyArrayList()

Change-Id: I2b31a9ab3c78de94dc18fc79d860c081005d7f55
Signed-off-by: Patrick Bänziger <patrick.baenziger@bsiag.com>
Task-Url: https://bugs.eclipse.org/bugs/show_bug.cgi?id=454544
Reviewed-on: https://git.eclipse.org/r/37838
Tested-by: Hudson CI
Reviewed-by: Jeremie Bresson <jbr@bsiag.com>