Add CopyOnWriteArrayList test to check get() return type

Checking that the items returned by CopyOnWriteArrayList.get()
have the right type, same as in the original collection that was
passed to the CopyOnWriteArrayList constructor.

Test: atest CopyOnWriteArrayListTest
Change-Id: I2101ee743d5b63cb932dbd97c4c9eceaad45ac85