You cannot call these functions with the API.
You can filter the work items in advance by adding a condition on the Workitem property of the time entry. If you report directly on the Projects, it can be a simple Compare condition with an In operator. If you report on the Project's work items, you can add a nested condition ( i.e. Workitem In (QueryExpression with a Where containing (Project In QueryExpression containing the ExpectedRevenue condition)).
Bare in mind that this will internally retrieve all work items of projects/projects that have an expected revenue and then filter Time Entries by them.
A better approach may be retrieving all Time Entries reported by the user in the date range (as you already did), and adding the Workitem.Project.ExpectedRevenue to the result fields. Then you can filter the results easily by testing the ExpectedRevenue field.
Hope this helps.