Change gtest launcher, telemetry unittests to run in parallel and retry failures by default.

Previously, gtest-based tests would not run tests in parallel or retry failures
by default unless you specified the --test-launcher-bot-mode flag

This patch changes the behavior so that we run tests in parallel and retry failures by
default if we are running *all* of the tests (i.e.,  --gtest_filter was *not* specified).

You can still pass --test-launcher-jobs=X to control how many tests run in parallel,
and --test-launcher-retry-limit=0 to turn retries off and 
--test-launcher-retry-limit=X to control how many times to retry.

R=jam@chromium.org, phajdan.jr@chromium.org, ojan@chromium.org, tonyg@chromium.org
BUG=402089

Review URL: https://codereview.chromium.org/469533002

git-svn-id: http://src.chromium.org/svn/trunk/src/base@289839 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
Parse shmmax as a uint64

A recent Linux kernel change changed this to a number larger than 63 bits which causes us to compute 0 size.

I kept the size_t overflow check for cases where size_t is 32-bits.

BUG=403869
R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/471893003

git-svn-id: http://src.chromium.org/svn/trunk/src/base@289903 4ff67af0-8c30-449e-8e8b-ad334ec8d88c