Skip 'make test' on JVM backend

It doesn't finish in a reasonable time and there are various failures
for those tests that were run. It's just a big waste of resources.

*If* running 'make test' on the JVM backend gets in a better shape in
the future, it could be re-enabled easily.

.travis.yml

@@ -22,7 +22,7 @@ addons:
 script:
     - perl Configure.pl $RAKUDO_OPTIONS --moar-option=--cc=$(command -v gcc-6 >/dev/null 2>&1; if [ $? -eq 1 ]; then printf "gcc"; else printf "gcc-6"; fi)
     - "make install"
-    - (cd ~/build/rakudo/rakudo/ && prove -e ~/build/rakudo/rakudo/install/bin/perl6 -vlr t)
+    - if [[ $RAKUDO_OPTIONS =~ jvm ]]; then echo "make test is skipped on the jvm backend"; else (cd ~/build/rakudo/rakudo/ && prove -e ~/build/rakudo/rakudo/install/bin/perl6 -vlr t); fi
 
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