test: mark test flaky on FreeBSD
test: mark test flaky on FreeBSD

Mark test-net-socket-local-address flaky on FreeBSD. It times out with
some frequency on CI.

Ref: https://github.com/nodejs/node/issues/2475
PR-URL: https://github.com/nodejs/node/pull/4016
Reviewed-By: Johan Bergström <3e38e5ce4283f06de4b83ad13af081abc5e16740@bergstroem.nu>
Reviewed-By: Ben Noordhuis <59bd0a3ff43b32849b319e645d4798d8a5d1e889@bnoordhuis.nl>

dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node,dreamllq/node