If range is a palindrome larger than lengthMin.
assert(!`ab`.isPalindrome); assert(`a`.isPalindrome); assert(`åäå`.isPalindrome); assert(`áá`.isPalindrome); assert(`åäå`.isPalindrome); assert(``.isPalindrome); assert([1, 2, 2, 1].s[].isPalindrome); assert(![1, 2, 2, 1].s[].isPalindrome(5)); assert(``.isPalindrome(lengthMin: 0)); assert(!``.isPalindrome(lengthMin: 1));