[RenderScript] Test Float16 variants of Allocation copy functions

http://b/27251511

For Allocation-copy scenarios that are currently tested for short and
ushort, add tests for Float16 variants as well.

Change-Id: I1513c16fbb69219b8fb452b1b5acccb25a161f7c
(cherry picked from commit 58b96a2bb7d68db61aa9e61a9b934d1b8a42e73d)
3 files changed