bv2int: new options for bvand translation (#5096)

bv2int: new options for bvand translation (#5096)

Currently, (bvand x y) is translated into a sum of ITEs.
This PR introduces two more options for the translation of (bvand x y):

bv: cast the integer translations of x and y back to bit-vectors, do a bvand, and cast the result to integers.
iand: use the builtin iand operator.
These options are added to many of the tests, and some new tests are added.
In addition, some tests are cleaned up (e.g., removing --no-check-unsat-cores for satisfiable benchmarks).
Finally, some tests are moved from regress0 to regress2 because they take several seconds to complete (2 -- 10 seconds).