IT is both simplicial and quadrilateral...

So far, we were a bit sloppy about which basis we choose from the UFL
counterpart. This commit implements the necessary 1-to-1 mapping.

This reverts commit 05a2c7d3

This reverts commit 6a1e7cc9

This reverts commit f83a804e

The Exadune preconditioners cant handle one sided assembly for reasons.

Run the function call over multiple data sets.

Replace placeholders in template file with actual code. This makes it a lot
easier to restructure the benchmark.

This rewrite was necessary for the cases where the instruction contains a
reduction but the expression itself is not a reduction. Besides fixing this bug
it greatly reduces code duplication and increases code quality.

This just reverts to the old behaviour. The new implementation of loop
reordering doesn't need that anymore.