Handle #REF! As Argument to COUNTIF, AVERAGEIF, SUMIF

[oleibman]

Fix #4381. The report refers to COUNTIF, but AVERAGEIF and SUMIF, which are implemented in the same module, exhibit the same behavior. (There may be others, but, for now, I will just fix those 3.)

Most methods which implement Excel functions should accept mixed arguments, so that they won't throw exceptions when calculated. Of course, MS often doesn't give much guidance as to how unexpected arguments should be handled. It at least seems clear that MS will often substitute #REF! for some arguments, and will return #REF! as the result in such cases. My test indicates that a formula using, say, #DIV/0! in lieu of #REF! will cause Excel to deem the spreadsheet corrupt. So, I think I am just going to deal with #REF! and let other unexpected values continue to throw exceptions.

This is:

• a bugfix
• a new feature
• refactoring
• additional unit tests

Checklist:

• Changes are covered by unit tests
  • Changes are covered by existing unit tests
  • New unit tests have been added
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change and a link to the pull request if applicable
• Documentation is updated as necessary