bpf_dsl: Change bpf_dsl_unittests into actual standalone unit tests

bpf_dsl: Change bpf_dsl_unittests into actual standalone unit tests

[Reland of https://codereview.chromium.org/940693004]

Previously they were more like integration tests that relied on
seccomp-bpf for installing the policies and executing them via live
system calls.

BUG=449357
Committed: https://crrev.com/bdc0f56e733a3fe99ab06670bd698d6880315fa4
Cr-Commit-Position: refs/heads/master@{#319537}

[mdempsky, 2015-03-06 21:40:59]

mdempsky@chromium.org changed reviewers:
+ jln@chromium.org

[jln (very slow on Chromium), 2015-03-06 21:53:04]

Rubberstamp lgtm based on previous review.

[mdempsky, 2015-03-06 21:53:26]

The CQ bit was checked by mdempsky@chromium.org

[commit-bot: I haz the power, 2015-03-06 21:53:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/987603003/1

[commit-bot: I haz the power, 2015-03-07 00:24:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-03-07 00:25:37]

Patchset 1 (id:??) landed as
https://crrev.com/bdc0f56e733a3fe99ab06670bd698d6880315fa4
Cr-Commit-Position: refs/heads/master@{#319537}