To better accommodate very slow buildbots, a parameter is added in PR-1722 to scale up the timeout durations where they are necessary on a per-machine basis.

Relevant tests have a timeout set to some default number of seconds times a multiplier value.

The multiplier value can be controlled by the environment variable 'CONF_TIMEOUT_MULTIPLIER' which defaults to a multiplier of 1.0 if not set.  On buildbots, this environment variable can be set by defining a parameter by that name in the buildbot configuration file for a machine.  Otherwise, this environment variable can be set in the usual way before running tests on non-buildbot machines.