Add new methods to BuildPerfTest class for running a shell
command and logging its output.
(From OE-Core rev: 8f0b11ba1266f9c650cf34d9b394d72009ee7207)
Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>