Fix class loader visibility issue in JAR loading.

Author: jnthn

src/vm/jvm/runtime/org/perl6/nqp/runtime/BootJavaInterop.java

@@ -222,7 +222,10 @@ protected void finishClass(ClassContext cc) {
         //} catch (java.io.IOException e) {
         //    e.printStackTrace();
         //}
-        cc.constructed = new ByteClassLoader(bits).findClass(cc.className.replace('/','.'));
+        cc.constructed = (cc.target == null
+                ? new ByteClassLoader(bits)
+                : new ByteClassLoader(bits, cc.target.getClassLoader())
+            ).findClass(cc.className.replace('/','.'));
         try {
             cc.constructed.getField("constants").set(null, cc.constants.toArray(new Object[0]));
         } catch (ReflectiveOperationException roe) {

src/vm/jvm/runtime/org/perl6/nqp/runtime/ByteClassLoader.java

@@ -7,6 +7,11 @@ public ByteClassLoader(byte[] bytes) {
         this.bytes = bytes;
     }
 
+    public ByteClassLoader(byte[] bytes, ClassLoader parent) {
+        super(parent);
+        this.bytes = bytes;
+    }
+    
     public Class<?> findClass(String name) {
         return defineClass(name, this.bytes, 0, this.bytes.length);
     }