Rename 'timeoutTest' to 'OpFromCallback'.

The test implies nothing about timeouts at all, just a large amount of
operations from within the callback.

Change-Id: I71aeb7f94a0539af0605ad0260277edd27fd6d0d
Reviewed-on: http://review.couchbase.org/42282
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>