gtest: Import sources from gtest 1.6.0.

The upstream of gtest has decided that the intended usage model is for
projects to import the source and use it, which is reflected in their
recent removal of the gtest-config tool.

Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Chad Versace <chad.versace@linux.intel.com>
10 files changed