This modernizes python code without breaking Py2 compat.

Ran with command:

futurize --stage1 -w tools/testrunner/testpro

Manual fixup to util_unittest to modify import paths and change to
absolute imports.

Bug: v8:9871
Change-Id: I2ac29622aff5daebc9dc42145c1d96dff8258546
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2252549Reviewed-by: Tamer Tas <tmrts@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68492}

This is a reland of 3fc96631

The private method on_event in timeout proc is now renamed to be truly
private.

Original change's description:
> [test] Print hanging tests on linux on test-runner termination
>
> This will print the list of processes still running before and after
> joining workers during termination. This will help debugging hanging
> tests during flake-bisect or with num-fuzzer, which both terminate
> on total timeout and currently still sometimes hang without printing
> processes.
>
> Bug: v8:8292
> Change-Id: I124b65fa35b8d7a6aa198fcf50f2c20df94dc51a
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1735312
> Reviewed-by: Tamer Tas <tmrts@chromium.org>
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63065}

Bug: v8:8292
Change-Id: Ibad1172666d6f4d2c07884a54edfe9d6499b57fe
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1735318Reviewed-by: Tamer Tas <tmrts@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63072}

TBR=tmrts@chromium.org
NOTRY=true

Bug: v8:9098
Change-Id: I69d9cd21ad70357a77b45e97393949f1cfbab529
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1557137Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60669}

This is a partial revert of:
https://crrev.com/c/890938 and https://crrev.com/c/893982

Before this CL, the test runner blocked on ongoing tests in order to
process their results after an internal timeout. However, the logic
required for this feature was overly complicated and prevented an
acceptable implementation for fast aborts. Furthermore, also the fuzzers
suffered from timeouts on swarming due to hanging tests.

Instead, we now abort immediately on internal timeout (used on
fuzzers), SIGINT (Ctrl-C) and SIGTERM. Ongoing tests are immediately
terminated and their results are disregarded. On SIGTERM and SIGINT,
we return with non-zero exit codes, and zero on internal timeout.

This will also properly return json output, when the external hard
timeout is reached on swarming (causes SIGTERM).

TBR=sergiyb@chromium.org

Bug: v8:7423, chromium:813065
Change-Id: Ib20f835f58a0970693bdd3b21dc5d766d8e115d8
Reviewed-on: https://chromium-review.googlesource.com/924852Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51399}

Bug: v8:6917
Change-Id: If91defd11c91fd26bdbacc146992745ea772a941
Reviewed-on: https://chromium-review.googlesource.com/890938Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michał Majewski <majeski@google.com>
Cr-Commit-Position: refs/heads/master@{#50985}

This is a reland of 4de2be99.

Original change's description:
> [test] Move timeout control to timeout processor
> 
> Bug: v8:6917
> Change-Id: I03be38be952f0d59eb20fa98102ef09ca795de40
> Reviewed-on: https://chromium-review.googlesource.com/883446
> Commit-Queue: Michał Majewski <majeski@google.com>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#50848}

Bug: v8:6917
Change-Id: I52798af84991d4815910e9da5f4837329cdb3c96
Reviewed-on: https://chromium-review.googlesource.com/885765Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michał Majewski <majeski@google.com>
Cr-Commit-Position: refs/heads/master@{#50870}

This reverts commit 4de2be99.

Reason for revert: Testing stops too early now, e.g. here after 2 min:
https://build.chromium.org/p/client.v8.clusterfuzz/builders/V8%20NumFuzz/builds/32

Original change's description:
> [test] Move timeout control to timeout processor
> 
> Bug: v8:6917
> Change-Id: I03be38be952f0d59eb20fa98102ef09ca795de40
> Reviewed-on: https://chromium-review.googlesource.com/883446
> Commit-Queue: Michał Majewski <majeski@google.com>
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#50848}

TBR=machenbach@chromium.org,sergiyb@chromium.org,majeski@google.com

Change-Id: I6a925866476c69b3b50aa08e99facca0eaaa396b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6917
Reviewed-on: https://chromium-review.googlesource.com/884082Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50851}

Bug: v8:6917
Change-Id: I03be38be952f0d59eb20fa98102ef09ca795de40
Reviewed-on: https://chromium-review.googlesource.com/883446
Commit-Queue: Michał Majewski <majeski@google.com>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50848}