Code review request [JDK 9] 8042449 Issue for negative byte major record version

[Xuelei Fan]

Hi,

Please review this simple but interesting fix:
  http://cr.openjdk.java.net/~xuelei/8042449/webrev.00/

During the checking of invalid record version, a byte to byte comparing
is coded as:
   if (...
      recordVersion.major > ProtocolVersion.MAX.major) {
      throw new SSLException
   }

"recordVersion.major" and "ProtocolVersion.MAX.major" is byte type,
which is signed.  If the major version is "0xa9", recordVersion.major is
a negative value (-87).  If ProtocolVersion.MAX.major is positive, the
checking above does not work any more.

This fix converts the version number to positive value before make the
comparing.

Thanks,
Xuelei