Review request for JDK-8025515

[Hannes Wallnoefer]

Please review my patch for JDK-8025515: Performance issues with 
Source.getLine().

http://cr.openjdk.java.net/~hannesw/8025515/webrev.01/

With this Source.getLine() is only gets used in placed that are not 
performance sensitive.

Thanks,
Hannes