Merged in ruslantproductengine/viewer-cougar-4cr-5 (pull request #55)

SL-11160 Test build viewer can crash (assert) on multi selection

Approved-by: Andrey Lihatskiy <andreylproductengine@lindenlab.com>
Approved-by: Andrey Kleshchev <andreykproductengine@lindenlab.com>
Approved-by: Simon Linden <simon@lindenlab.com>