fix($compile): workaround for IE11 MutationObserver

IE11 MutationObserver breaks consecutive text nodes into several text nodes.
This patch merges consecutive text nodes into a single node before
looking for interpolations.

Closes angular#11781

Author: lgalfaso

src/ng/compile.js

@@ -1540,6 +1540,11 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
           }
           break;
         case NODE_TYPE_TEXT: /* Text Node */
+          // Workaround for IE11 #11781
+          while (node.parentNode && node.nextSibling && node.nextSibling.nodeType === NODE_TYPE_TEXT) {
+            node.nodeValue = node.nodeValue + node.nextSibling.nodeValue;
+            node.parentNode.removeChild(node.nextSibling);
+          }
           addTextInterpolateDirective(directives, node.nodeValue);
           break;
         case NODE_TYPE_COMMENT: /* Comment */

test/ng/compileSpec.js

@@ -2762,6 +2762,16 @@ describe('$compile', function() {
     }));
 
 
+    it('should handle consecutive text elements as a single text element', inject(function($rootScope, $compile) {
+      var base = jqLite('<div></div>');
+      base[0].appendChild(document.createTextNode('Lucas {{1+'));
+      base[0].appendChild(document.createTextNode('2}} Lucas'));
+      element = $compile(base)($rootScope);
+      $rootScope.$digest();
+      expect(element.text()).toBe('Lucas 3 Lucas');
+    }));
+
+
     it('should support custom start/end interpolation symbols in template and directive template',
         function() {
       module(function($interpolateProvider, $compileProvider) {