libjava: fix locale handling when sorting JNI methods

libjava: fix locale handling when sorting JNI methods

When building under LANG=cs_CZ.UTF-8, the JNI method check fails:

/bin/bash ../../scripts/check_jni_methods.sh
Found a problem with the JNI methods declared and implemented.
(<) missing in implementation, (>) missing in header files
> Java_gnu_java_awt_peer_gtk_GtkClipboard_advertiseContent
> Java_gnu_java_awt_peer_gtk_GtkClipboard_initNativeState
... lots more ...

While the sed commands are run under LC_ALL=C, the two sort commands are
not, and they end up producing unexpected output (for the test).  Once we
run both under LC_ALL=C, the check passes.  While we're here, we can also
combine latter the `sort|uniq` into `sort -u` to match the earlier code.

URL: https://bugs.gentoo.org/563710
Reported-by: Miroslav Šulc <fordfrog@gentoo.org>
From-SVN: r229388