[tests] fix compile-jvm.hxml relying on compile-java.hxml having been run

Otherwise it would fail with "Error: Java lib native_java/native.jar not found".

tests/unit/compile-jvm.hxml

@@ -1,3 +1,8 @@
+#java native build
+-cmd "haxelib run hxjava native_java/hxjava_build.txt --out native_java/native"
+
+--next
+
 compile-each.hxml
 --main unit.TestMain
 --java-lib native_java/native.jar