fix(merge): ensure that jqlite->jqlite and DOM->DOM

Previously we were wrapping DOM elements into jqlite objects when cloning
and vice versa.

Fixes #12286 (comment)

src/Angular.js

@@ -360,8 +360,10 @@ function baseExtend(dst, objs, deep) {
           dst[key] = new Date(src.valueOf());
         } else if (isRegExp(src)) {
           dst[key] = new RegExp(src);
+        } else if (src.nodeName) {
+          dst[key] = src.cloneNode(true);
         } else if (isElement(src)) {
-          dst[key] = src[0] ? jqLite(src).clone()[0] : jqLite(src).clone();
+          dst[key] = jqLite(src).clone();
         } else {
           if (!isObject(dst[key])) dst[key] = isArray(src) ? [] : {};
           baseExtend(dst[key], [src], true);

test/AngularSpec.js

@@ -636,7 +636,9 @@ describe('angular', function() {
       expect(dst.jqObject).not.toBe(src.jqObject);
 
       expect(isElement(dst.element)).toBeTruthy();
+      expect(jqLite(dst.element)).not.toBe(dst.element); // i.e it is a DOM element
       expect(isElement(dst.jqObject)).toBeTruthy();
+      expect(jqLite(dst.jqObject)).toBe(dst.jqObject); // i.e it is a jqLite/jquery object
     });
   });