Don't check for java nor javac when --disable-java is specified.
This avoid annoying dialogs on macOS when Java has not been installed so far.
Reported by Iain Sandoe <idsandoe@googlemail.com> in
<https://gcc.gnu.org/pipermail/gcc/2022-June/238929.html>.
* gettext-runtime/configure.ac: When JAVA_CHOICE is 'no', bypass the gt_JAVACOMP
and JAR tests.
* gettext-tools/configure.ac: When JAVA_CHOICE is 'no', bypass the gt_JAVAEXEC,
gt_JAVACOMP, and JAR tests.
