[NF] Typing improvements.

- Remove if-branches with known false conditions during typing,
  to avoid typing potentially invalid equations.
- Handle der of arrays.
- Try to evaluate function output types better.
- Expand fill/ones/zeros when possible.
- Don't expand array equations containing function calls.

Belonging to [master]:
  - #2113
  - OpenModelica/OpenModelica-testsuite#826

Author: perost