Add unit test for ReadFileIntoMemory and WriteFileFromMemory

The code is refactored to support mocking the transferDataHost API.
Unit testcases are added for ReadFileIntoMemory and WriteFileFromMemory
responder implementations.

Signed-off-by: Tom Joseph <tomjoseph@in.ibm.com>

Change-Id: Iab9966a7aea602cc2abcdf386f077001368e66d9
6 files changed