Use --ast in forge build in Kontrol

[palinatolmach]

As discussed in #399, starting from foundry-rs/foundry#7197, Foundry doesn't include AST in the output of forge build by default. If the AST is not present in solc-produced files, #399 added a descriptive error message suggesting that the user should add ast = true to foundry.toml.

However, for the AST to be generated automatically, we could also include --ast into the set of flags we are calling forge build with:

kontrol/src/kontrol/foundry.py

Line 252 in fc9a495

run_process(['forge', 'build', '--root', str(self._root)], logger=_LOGGER)

The --ast flag was only added in foundry-rs/foundry#7197, so it's not backwards compatible, and would require checking a version of Foundry being used first.

[palinatolmach]

Alternatively, we can add a --build-info flag to forge build, which is backward compatible, but generates additional information (such as the build info file itself) — it doesn't increase the execution time for forge build on our integration test suite, but occupies more disk space: