GitLab

1. /pkg, /svc and /config/ssl are now cloned to Context processes.
   https://crrev.com/1149262 removed FDIO_SPAWN_CLONE_NAMESPACE.
   As result the context process was failing to open /pkg/icudtl.dat.
2. Added FDIO_SPAWN_CLONE_JOB flag - job needs to be cloned so the
   context process can start its own children.
3. Updated SandboxPolicyFuchsia not to clone /tmp - it doesn't appear
   to be necessary for any sandboxed processes.
4. Removed FDIO_SPAWN_CLONE_STDIO for Context and sandboxed processes.
   Instead stderr is added fds_to_map.

Bug: 852145, 869216, 868556
Change-Id: I89c429231cd0e295247c80f12e587e1c7335456b
Reviewed-on: https://chromium-review.googlesource.com/1155967
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579872}