Annotate parameters of Immutable collections copyOf() of()

Annotate parameters of Immutable collections copyOf() of()

Those methods will throw NPEs if null is passed.
Also fix a few warnings that were introduced by these new annotations.

Change-Id: I73efaa5507b1dfcf9da41c86dc93bbd8ea8b3c27
Signed-off-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/60568
Reviewed-by: Hudson CI
Reviewed-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Tested-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>