Force javac to use -encoding UTF-8

Since I3778f9c8 we have had non-ASCII characters in our source files.
javac may decide to read the locale from its environment, which fails
on such source files, causing warnings at best and test failures at
worst.

Hack our default java rule defs to pass -encoding.

Change-Id: I53dfd2d551eed7c1c1fa8ef5cfcfb726d67e3a62
1 file changed