Tests: fixed tests to run as root.

- The mode of testdir was changed to allow reading from other users/groups.
- The java multipart test now uploads the file into an app writable dir.
- The build directory was made readable for other users.
- The python environment test now uses the HOME env var instead of PWD
  because the latter is not set by the root shell (/bin/sh) by default.
- The node `node_modules` directory now is copied into the `testdir` instead
  of using symlinks.

test/unit/applications/lang/node.py

@@ -22,13 +22,15 @@ class TestApplicationNode(TestApplicationProto):
             self.current_dir + '/node/' + script, self.testdir + '/node'
         )
 
-        # link modules
+        # copy modules
 
-        os.symlink(
+        shutil.copytree(
             self.pardir + '/node/node_modules',
             self.testdir + '/node/node_modules',
         )
 
+        self.public_dir(self.testdir + '/node')
+
         self._load_conf(
             {
                 "listeners": {"*:7080": {"pass": "applications/" + script}},