Review request for JDK-8143304: Random failures when script size exceeds token limits

[Hannes Wallnoefer]

Please review JDK-8143304: Random failures when script size exceeds 
token limits:

http://cr.openjdk.java.net/~hannesw/8059934/webrev/

This assigns 28 bits to both the position and the length in the parser 
token, and makes sure source files don't exceed this limit in the parser.

Previously we used 32 bits for the position and only 24 for the length. 
The thinking behind that probably was that a token would never be as 
long as the whole script but that turns out to be wrong (like for the 
main script function, or a very long object or array literal).

Thanks,
Hannes