Adding fileutils.h support for absolute paths

This CL completes the effort done in http://review.webrtc.org/858014/ to make tests find the resources in various scenarios.

Slightly modified tests since there were a bit confusing and that their description conflicted with the current functionality.

BUG=Tests that are run with full absolute paths cannot find resources.
TEST=Local tests using absolute paths + trybots

Review URL: https://webrtc-codereview.appspot.com/878007

git-svn-id: http://webrtc.googlecode.com/svn/trunk@2936 4adac7df-926f-26a2-2b94-8c16560cd09d
4 files changed