internals: remove tail recursion from stripAssignmentFlag()
internals: remove tail recursion from stripAssignmentFlag()

dleffler/scssphp,dleffler/scssphp,webdevid/scssphp,kkkyyy03/scssphp,dleffler/scssphp,g105b/scssphp,leafo/scssphp,g105b/scssphp,webdevid/scssphp,g105b/scssphp,leafo/scssphp,leafo/scssphp,webdevid/scssphp