Add method for results containing binary data

The new method allows collectors to write their binary data results
without having to handle the encoding and breaking the abstraction.

A default implementation is provided for backwards compatibility with
CTS on older branches.

Test: atest CtsEdiHostTestCases GtsEdiHostTestCases
Change-Id: Ia7b1e5d7484a17c2d2454b9623fb8ce17c1dc72a
1 file changed