Use local variables instead of function calls

Makes static analysis (LLVM's scan-build) happy.
Avoid pointer garbage
Clarify code

And remove a dead assignment to and1
execfreq: Remove unused attribute max from int_factors.
cleanup: Fix coding style.
execfreq: Assign min_non_zero and add asserts to check initialization.
becopyopt: Initialize execfreq int factors before trying to use them.

We called get_block_execfreq_int() with the int factors struct
completely filled with zeroes, so we always got an int execfreq
of 0.  co_get_costs_exec_freq() therefore always returned 1, making
it equivalent to co_get_costs_all_one().
lpp: Do not allow Gurobi to violate the optimality.