Fix and extend scheduler test infrastructure

Commit 168e457b broke one of the scheduler tests, as well as other job options that weren't added as tests. This merge request fixes this aftermath.

Highlights:

1. In all scenarios:

• avoid repetitive data input/output declaration each time an algorithm instance is re-used in the graph of precedence rules;

2. In ATLAS MC data reconstruction scenario:

• declare as a test;
• hide all occurrences of '::' operator used by data types specifications (otherwise such data items are misinterpreted as alternatives);
• remove in-place data modification pattern from the data flow graph (all such occurrences were in fact removed earlier, except one, which is now also removed)