ip-address: Address6 matches a zone identifier in quadratic time ahead of its length limit, allowing a single long string to stall the process

Summary new Address6 and Address6.isValid strip a zone identifier with the pattern /%.$/ before they apply the 45-character length limit. When the string holds many % characters followed by a line terminator, the pattern is retried from every % and each attempt scans to the line terminator before...