heuristics, mapping, s2o: correcting dupplicate instruction bug

Some instructions were preset several times in the mapping due to some wrong coalscecing, essencially because we did not perform the same number of benchmark for kernel's instruction and for the others, leading to difficulties in finding the classe corresponding to the saturating instructiong. This commit disables the ""smart"" behaviour that was not generating benchmarks for saturating instructions, and ensure that saturating instructions are always representents of their classes.