ACSL parser and translator improvements

[zafer-esen]

This PR updates the ACSL grammar and translator with several fixes and improvements.

• Terms and predicates are merged into a single Expr. The parser now can handle operator precedences - before, parentheses were required almost in all expressions.
• Better parsing of C types - most C types should now be supported (largely untested).
• Foundation for better error messages - source code locations are added to the translator.
• Fixed possibly other issues in the grammar, there were ~400 shift/reduce and reduce/reduce conflicts, now there are only 7 shift/reduce conflicts which are expected.

The translator still leaves large parts of ACSL unimplemented, but extensions should now be more straightforward to implement.

[zafer-esen]

A hidden change in this PR, regression tests will now continue until all tests are completed. This is better for getting feedback on exactly which tests failed.