Take care with structure alignments, we should allocate cells with posix_memalign and when passing aligned structs, like runner, do this by pointer not value, not sure how aligned memory will work on the stack

Was crashing on COSMA6, so AVX not AVX2 this time

Note part of this squashes the report 'note: The ABI for passing parameters with 64-byte alignment has changed in GCC 4.6' when calling test_boundary_conditions()