[infra-tests] Restore use of setTimeout in reftest-wait test (#5093)

As this is a reference test, it does not have access to testharness.js
for step_timeout. Normally reference tests should not need to sleep for
time periods anyway, however this is an infrastructure test and so just
whitelist the usage.

View on GitHub: https://github.com/w3c/web-platform-tests/pull/5093

Received on Wednesday, 8 March 2017 17:04:22 UTC