Add device_unittests target to linux_default_tests list.

This is a target I converted to GN and it is known to run fine.

Tested on Linux with the following command lines:

$ gn gen out-gn
$ ninja -C out-gn device_unittests
$ out-gn/device_unittests

BUG=None
TEST=see above
R=dpranke@chromium.org
TBR=brettw@chromium.org

Review URL: https://codereview.chromium.org/990653002

Cr-Commit-Position: refs/heads/master@{#319772}
1 file changed