oeqa/selftest/runcmd: Tweal test timeouts

Load on the autobuilder meant we see occasionaly timeout issues with these tests.
Slightly increase the test timeouts to better reflect the real world timings we
see.

[YOCTO #14262]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit fccd2ade)
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>