Update attribute whitelist

[Scott-Guest]

• Add no-evaluators, preserves-definedness, and structural to the attribute whitelist
• Update K frontend tests to pass with --pedantic-attributes enabled
  • The only test which would still fail is regression-new/issue-1169 because it generates a K file with -E, which does not re-emit group(_), but merging Emit user-defined groups as group(_) #3441 will fix that.