[Android] Get renderers working again under seccomp-bpf.

Android 5.0 added some additional prctl()s that are used by the framework. This
also permits __NR_set_tid_address and fstat().

BUG=437067,166704
R=jln@chromium.org

Review URL: https://codereview.chromium.org/775943004

Cr-Commit-Position: refs/heads/master@{#306895}
2 files changed