This is a reland of 0db74d49.

Original change's description:
> [test] Random seed processor
> 
> 1. --total-timeout-sec now available for ./run-tests.py. It can be
> useful with infinite seed stressing
> 2. random seed dropped from the context. Now JSON progress indicator
> gets it from the list of command args.
> 
> Bug: v8:6917
> Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
> Change-Id: I73e535bc8face9b913c696b8d5e3a246fa231004
> Reviewed-on: https://chromium-review.googlesource.com/888524
> Commit-Queue: Michał Majewski <majeski@google.com>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#50964}

Bug: v8:6917
Change-Id: I1ea376a4abffce5ab65f4834ea7e6d6011765ffa
Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng
Reviewed-on: https://chromium-review.googlesource.com/894204Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michał Majewski <majeski@google.com>
Cr-Commit-Position: refs/heads/master@{#50978}