add DefineClass to test suite

As reported on the discussion group, there is a problem with the
ClassLoader.defineClass implementation sunch that this test is not
currently passing, at least for the mode=debug and bootimage=true
builds.  I plan to address these failures soon, but I wanted to add a
test first to make sure I could reproduce them.

test/DefineClass.java

@@ -0,0 +1,52 @@
+import java.io.IOException;
+import java.io.File;
+import java.io.FileInputStream;
+
+public class DefineClass {
+  private static File findHello(File directory) {
+    File[] files = directory.listFiles();
+    for (File file: directory.listFiles()) {
+      if (file.isFile()) {
+        if (file.getName().equals("Hello.class")) {
+          return file;
+        }
+      } else if (file.isDirectory()) {
+        File result = findHello(file);
+        if (result != null) {
+          return result;
+        }
+      }
+    }
+    return null;
+  }
+
+  private static byte[] read(File file) throws IOException {
+    byte[] bytes = new byte[(int) file.length()];
+    FileInputStream in = new FileInputStream(file);
+    try {
+      if (in.read(bytes) != (int) file.length()) {
+        throw new RuntimeException();
+      }
+      return bytes;
+    } finally {
+      in.close();
+    }
+  }
+
+  public static void main(String[] args) throws Exception {
+    byte[] bytes = read(findHello(new File(System.getProperty("user.dir"))));
+    Class c = new MyClassLoader(DefineClass.class.getClassLoader()).defineClass
+      ("Hello", bytes);
+    c.getMethod("main", String[].class).invoke(null, (Object) new String[0]);
+  }
+
+  private static class MyClassLoader extends ClassLoader {
+    public MyClassLoader(ClassLoader parent) {
+      super(parent);
+    }
+
+    public Class defineClass(String name, byte[] bytes) {
+      return super.defineClass(name, bytes, 0, bytes.length);
+    }
+  }
+}