base: Use one-shot kqueue on macOS
base: Use one-shot kqueue on macOS

The underlying reason requiring that one-shot usage be disabled (#13903)
has been fixed.

Closes #15768.

sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc,sdiehl/ghc