This test uses find_unused_port() which is inherently racey, so retry
it a few times before failing.
[ YOCTO #14840 ]
(From OE-Core rev: efac044cabdbe77556a0b9903595fd602f39ac8d)
Signed-off-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>