RFR: 8147962: URL should handle lower-casing of protocol locale-independently

[Claes Redestad]

Hi,

using String.toLowerCase() in URL allows some strings to lower-case to a 
string that'd be invalid, e.g. "FILE".toLowerCase() -> "f\u0131le" in 
turkish locales.

This patch suggests using the locale-independent 
String.toLowerCase(Locale.ENGLISH) instead, since only a-z and A-Z are 
legal alphabeticals according to spec.

Webrev: http://cr.openjdk.java.net/~redestad/8147962/webrev.01/
Bug: https://bugs.openjdk.java.net/browse/JDK-8147962

Thanks!

Claes