First failures on net_unittests appear to come from the build:
https://luci-milo.appspot.com/buildbot/internal.client.clank/asan-clang-phone/2836

with a small CL range:
http://test-results.appspot.com/revision_range?start=475256&end=475260

+thakis could this be related with your change?

r475256 Reland of Pass -Oz flag to Clang when targeting Android.

It's possible. I'll take a look.

Looks like this stopped happening: https://luci-milo.appspot.com/buildbot/internal.client.clank/asan-clang-phone/?limit=200

(Also, I tried to repro this locally and failed. From the dates, the failures don't quite line up with the -Oz landing either.)