[TestSuite] Testing SDK function submission

Test the following scenarios in the function submission context:

• Submit a non-existent function
• Submit fn to a non-existent endpoint
• Submit fn to an endpoint not owned by the user
• Submit fn to an offline endpoint (we don't report endpoint status at this point. function will be 'pending' and no further info is expected at this time)
• Submit functions rapidly, to trigger throttling on the web-service side.