8160953: Update build-nagen-eclipse task to work with JDK 9

Reviewed-by: lagergren, sundar

nashorn/make/build-nasgen.xml

@@ -43,14 +43,14 @@
         </java>
     </target>
 
-    <target name="run-nasgen-eclipse">
+    <target name="run-nasgen-eclipse" depends="load-properties">
         <mkdir dir="${basedir}/build/eclipse/.nasgentmp"/>
 
         <java classname="jdk.nashorn.internal.tools.nasgen.Main" fork="true" failonerror="true">
             <classpath>
                 <pathelement location="${basedir}/buildtools/nasgen/dist/nasgen.jar"/>
             </classpath>
-            <jvmarg value="-Xbootclasspath/p:${basedir}/build/eclipse"/>
+            <jvmarg line="${nasgen.module.imports}"/>
             <arg value="${basedir}/build/eclipse"/>
             <arg value="jdk.nashorn.internal.objects"/>
             <arg value="${basedir}/build/eclipse/.nasgentmp"/>

nashorn/make/build.xml

@@ -27,11 +27,14 @@
   <import file="build-nasgen.xml"/>
   <import file="code_coverage.xml"/>
 
-  <target name="init-conditions">
+  <target name="load-properties">
     <!-- loading locally defined resources and properties. NB they owerwrite default ones defined later -->
     <property file="${user.home}/.nashorn.project.local.properties"/>
 
     <loadproperties srcFile="make/project.properties"/>
+  </target>
+
+  <target name="init-conditions" depends="load-properties">
     <path id="nashorn.jar.path">
          <pathelement location="${nashorn.jar}"/>
     </path>