Raise default DeleteIndex Timeout

Currently the timeout for an delete index operation is set to 10 seconds.
Yet, if a full flush is running while we delete and index this can
easily exceed 10 seconds. The timeout is not dramatic ie. the index
will be deleted eventually but the client request is not acked which
can cause confusion. We should raise it to prevent unnecessary confusion
especially in client tests where this can happen if the machine is pretty busy.

The new timeout is set to 60 seconds.

Closes #3498
Fix test include pattern to include *Test.class

We missed *Test.class which is not our convention but we could miss
some tests. We should better include the *Test.class tests as well.
Fix assert to check the deviation rather than the absolute difference.

Deviation should be less or equal to 0.01 ~ 1% after the cast.