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}