[11u] RFR 8190737:use unicode version of the canonicalize() function to handle long path on windows

[Schmelter, Ralf]

Hello,

please review this fix. The patch itself applied cleanly, but the LongBCP.java test needed an additional import statement.

Original bugreport: https://bugs.openjdk.java.net/browse/JDK-8190737
Original change: http://hg.openjdk.java.net/jdk/jdk/rev/9151fde080e6

Webrev of downport: http://cr.openjdk.java.net/~rschmelter/webrevs/8190737/webrev.jdk11u-dev.1/index.html

Best regards,
Ralf