Delete zombie udp_socket_unittest.
Delete zombie udp_socket_unittest.

This file was deprecated by corresponding apptests and was deleted in
https://codereview.chromium.org/722943004 .

It was accidentally ressurected when moving the network service
source-of-truth to Chromium - we carried over modifications and new
files, but didn't carry over deletions of whole files.

BUG=450356

Review URL: https://codereview.chromium.org/894093003

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#314601}

fujunwei/chromium-crosswalk,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,Fireblend/chromium-crosswalk,Fireblend/chromium-crosswalk,Chilledheart/chromium,ltilve/chromium,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,ltilve/chromium,Chilledheart/chromium,chuan9/chromium-crosswalk,ltilve/chromium,PeterWangIntel/chromium-crosswalk,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,hgl888/chromium-crosswalk,Chilledheart/chromium,PeterWangIntel/chromium-crosswalk,Chilledheart/chromium,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,Just-D/chromium-1,Fireblend/chromium-crosswalk,chuan9/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,fujunwei/chromium-crosswalk,chuan9/chromium-crosswalk,fujunwei/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,ltilve/chromium,PeterWangIntel/chromium-crosswalk,hgl888/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,TheTypoMaster/chromium-crosswalk,Fireblend/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,hgl888/chromium-crosswalk,ltilve/chromium,Pluto-tv/chromium-crosswalk,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,ltilve/chromium,chuan9/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,chuan9/chromium-crosswalk,Chilledheart/chromium,PeterWangIntel/chromium-crosswalk,Just-D/chromium-1,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,fujunwei/chromium-crosswalk,chuan9/chromium-crosswalk,Fireblend/chromium-crosswalk,chuan9/chromium-crosswalk,axinging/chromium-crosswalk,Just-D/chromium-1,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Pluto-tv/chromium-crosswalk,axinging/chromium-crosswalk,Chilledheart/chromium,Just-D/chromium-1,TheTypoMaster/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,hgl888/chromium-crosswalk,ltilve/chromium,Chilledheart/chromium,Just-D/chromium-1,Just-D/chromium-1,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Just-D/chromium-1,hgl888/chromium-crosswalk,ltilve/chromium,Fireblend/chromium-crosswalk,TheTypoMaster/chromium-crosswalk,TheTypoMaster/chromium-crosswalk