download graal.js so we can use it in tests

fetch.xml

@@ -319,9 +319,15 @@ Set -Ddest=LOCATION on the command line
     <f2 project="org.mozilla" archive="rhino"/>
   </target>
 
+  <target name="graal.js"
+          description="load Graal.js">
+    <f2 project="org.graalvm.js" archive="js"/>
+    <f2 project="org.graalvm.js" archive="js-scriptengine"/>
+  </target>
+
   <target name="script"
           description="load script languages (except Jython)"
-          depends="bsf,jruby,beanshell,rhino"/>
+          depends="bsf,jruby,beanshell,rhino,graal.js"/>
 
   <target name="debugging"
     description="internal Ant debugging"

lib/libraries.properties

@@ -42,6 +42,8 @@ bsh.version=2.0b5
 commons-net.version=3.6
 commons-logging.version=1.1
 commons-logging-api.version=${commons-logging.version}
+js.version=20.1.0
+js-scriptengine.version=${js.version}
 hamcrest-core.version=1.3
 hamcrest-library.version=${hamcrest-core.version}
 jai-core.version=1.1.3