Array constants are reconstructed in every time step

[Martin Sjölund]

{{{class A

constant Real i[:] = fill(1, 10000);
Real r = min(j*time for j in i);

end A;}}}

This will cause the array constant to be created in every single time step. The same goes for functions that take a lookup array + index.

Implementation tips: Use the common subexpression elimination that is performed for functions right now. We need something similar; but for Modelica arrays you need to do a top-down traversal instead of bottom-up due to the way arrays are represented in the C runtime.

[Martin Sjölund]

Fixed, this testcase now generates Real r = time. Also, array constants in simulation code are now referenced directly by pointer