RFR [S] 8131034: Cleanup in j.u.regex.Pattern.quote()

[Ivan Gerasimov]

Hello!

There's a minor issue in the current implementation of Pattern.quote() 
with possible numeric overflow when calculating initial capacity of 
StringBuilder.
With the fix, some slight optimizations were done and a few typos were 
fixed.

Would you please help review the fix?

BUGURL: https://bugs.openjdk.java.net/browse/JDK-8131034
WEBREV: http://cr.openjdk.java.net/~igerasim/8131034/00/webrev/

Sincerely yours,
Ivan