test($sanitize): skip nextSibling clobber test on Edge 16

In some circumstances, Edge 16 will not throw on clobbered
elements, because the nextSibling property is null. The exact
cause is currently unknown.

Author: Narretz

test/ngSanitize/sanitizeSpec.js

@@ -246,24 +246,37 @@ describe('HTML', function() {
       .toEqual('<p>text1text2</p>');
   });
 
-  it('should throw on clobbered elements', function() {
-    inject(function($sanitize) {
-      expect(function() {
-        $sanitize('<form><input name="parentNode" /></form>');
-      }).toThrowMinErr('$sanitize', 'elclob');
+  describe('clobbered elements', function() {
 
-      expect(function() {
-        $sanitize('<form><div><div><input name="parentNode" /></div></div></form>');
-      }).toThrowMinErr('$sanitize', 'elclob');
+    it('should throw on a form with an input named "parentNode"', function() {
+      inject(function($sanitize) {
 
-      expect(function() {
-        $sanitize('<form><input name="nextSibling" /></form>');
-      }).toThrowMinErr('$sanitize', 'elclob');
+        expect(function() {
+          $sanitize('<form><input name="parentNode" /></form>');
+        }).toThrowMinErr('$sanitize', 'elclob');
 
-      expect(function() {
-        $sanitize('<form><div><div><input name="nextSibling" /></div></div></form>');
-      }).toThrowMinErr('$sanitize', 'elclob');
+        expect(function() {
+          $sanitize('<form><div><div><input name="parentNode" /></div></div></form>');
+        }).toThrowMinErr('$sanitize', 'elclob');
+      });
     });
+
+    if (!/Edge\/16/.test(window.navigator.userAgent)) {
+      // Skip test on Edge 16 due to browser bug.
+      it('should throw on a form with an input named "nextSibling"', function() {
+        inject(function($sanitize) {
+
+          expect(function() {
+            $sanitize('<form><input name="nextSibling" /></form>');
+          }).toThrowMinErr('$sanitize', 'elclob');
+
+          expect(function() {
+            $sanitize('<form><div><div><input name="nextSibling" /></div></div></form>');
+          }).toThrowMinErr('$sanitize', 'elclob');
+
+        });
+      });
+    }
   });
 
   // See https://github.com/cure53/DOMPurify/blob/a992d3a75031cb8bb032e5ea8399ba972bdf9a65/src/purify.js#L439-L449