RFR 8224789 : Parsing repetition count in regex does not detect numeric overflow

[Ivan Gerasimov]

Hello!

When Pattern.compile() parses the repetition count in the expressions 
like '.{100}', '.{1,2}' or '.{3,}' it fails to detect numeric overflow 
if the result is still non-negative.

Could you please help review the patch?

BUGURL: https://bugs.openjdk.java.net/browse/JDK-8224789
WEBREV: http://cr.openjdk.java.net/~igerasim/8224789/00/webrev/

Also, reading a char at line 3274 is done with skip(), so the exception 
thrown at 3315 displays the position of the error more accurately.

-- 
With kind regards,
Ivan Gerasimov