Extend case stage completion condition tests

There are some stage completion conditions in cases used in tests, however, there are many condition types missing. A new StageCompletionConditionTest needs to be added to case management module. It will contain the following completion conditions:

• autocomplete with single task
• autocomplete without task autostart
• autocomplete with dynamic task in stage
• autocomplete with dynamic subprocess in stage
• no active tasks condition
• process variable condition
• case variable without caseFile prefix
• case variable with caseFile prefix
• case data definition ID
• case data variable