Fix fuzz max long test

[dpaiton]

Resolved Issues

Partially resolves these two:
#88
#45

Description

The fee rounding behavior was adjusted recently to more closely match solidity, but the order of operations was not exactly the same. This caused an occasional slight variation in output (usually off by 1e1), that compounded in situations where we were iteratively assessing fees such as max_long. In that case, the error would grow to as much as 1e5.

During my effort to find this bug I

• modified some math to use the e.g. .mul_down syntax instead of * where it was sufficiently complicated to require this to easily pattern match against Solidity.
• modified calculate_max_long to return errors instead of panic. This makes checks in the tests ugly, but that is a temporary problem until we purge the panics all-together (Improved Testing of the Rust SDK #20)
• purged the use of traced and trace_test which is helpful for debugging but was not actively being used and can slow down tests.

Review Checklists

Please check each item before approving the pull request. While going
through the checklist, it is recommended to leave comments on items that are
referenced in the checklist to make sure that they are reviewed.

• Testing
  • Are there new or updated unit or integration tests?
  • Do the tests cover the happy paths?
  • Do the tests cover the unhappy paths?
  • Are there an adequate number of fuzz tests to ensure that we are
    covering the full input space?
  • If matching Solidity behavior, are there differential fuzz tests that
    ensure that Rust matches Solidity?

[sentilesdal]

nice!