Improve acir_integration_tests

[codygunton]

Four of the the acir integration tests were skipped because they fail with

q: error: Could not open file ../../acir_tests/acir_tests/brillig_scalar_mul/target/program.json: No such file or directory

gzip: stdin: unexpected end of file
unknown file: Failure
C++ exception with description "Input is not large enough" thrown in the test body.

Also: it would be better to generate the list of tests. The tests are not frequently deleted, so this is not a high priority, but when they are the Bb tests will fail.