remotetest-874821: Move timing summary to helpers

Helps us show the timing summary whenever we run the tests.

Signed-off-by: Joe Walker <jwalker@mozilla.com>
remotetest-874821: Use requestId rather than id

'id' is very common and we don't want to confuse it with any other
ids that people use on any protocols.

Signed-off-by: Joe Walker <jwalker@mozilla.com>