fix($location): prevent infinite digest with IDN urls in Edge

Internationalized Domain Urls, for example Urls with Umlaut (Ä, Ö, Ü)
cause infinite digest in Edge 38.14393.0.0 because lastIndexOf doesn't
work correctly in this version. indexOf does, though.

Fixes angular#15217

Author: Narretz

src/ng/location.js

@@ -49,7 +49,7 @@ function parseAppUrl(relativeUrl, locationObj) {
 }
 
 function startsWith(haystack, needle) {
-  return haystack.lastIndexOf(needle, 0) === 0;
+  return haystack.indexOf(needle) === 0;
 }
 
 /**

test/ng/locationSpec.js

@@ -2450,10 +2450,11 @@ describe('$location', function() {
 
 
   describe('LocationHtml5Url', function() {
-    var locationUrl, locationIndexUrl;
+    var locationUrl, locationUmlautUrl, locationIndexUrl;
 
     beforeEach(function() {
       locationUrl = new LocationHtml5Url('http://server/pre/', 'http://server/pre/', 'http://server/pre/path');
+      locationUmlautUrl = new LocationHtml5Url('http://särver/pre/', 'http://särver/pre/', 'http://särver/pre/path');
       locationIndexUrl = new LocationHtml5Url('http://server/pre/index.html', 'http://server/pre/', 'http://server/pre/path');
     });
 
@@ -2465,6 +2466,13 @@ describe('$location', function() {
       // Note: relies on the previous state!
       expect(parseLinkAndReturn(locationUrl, 'someIgnoredAbsoluteHref', '#test')).toEqual('http://server/pre/otherPath#test');
 
+      expect(parseLinkAndReturn(locationUmlautUrl, 'http://other')).toEqual(undefined);
+      expect(parseLinkAndReturn(locationUmlautUrl, 'http://särver/pre')).toEqual('http://särver/pre/');
+      expect(parseLinkAndReturn(locationUmlautUrl, 'http://särver/pre/')).toEqual('http://särver/pre/');
+      expect(parseLinkAndReturn(locationUmlautUrl, 'http://särver/pre/otherPath')).toEqual('http://särver/pre/otherPath');
+      // Note: relies on the previous state!
+      expect(parseLinkAndReturn(locationUmlautUrl, 'someIgnoredAbsoluteHref', '#test')).toEqual('http://särver/pre/otherPath#test');
+
       expect(parseLinkAndReturn(locationIndexUrl, 'http://server/pre')).toEqual('http://server/pre/');
       expect(parseLinkAndReturn(locationIndexUrl, 'http://server/pre/')).toEqual('http://server/pre/');
       expect(parseLinkAndReturn(locationIndexUrl, 'http://server/pre/otherPath')).toEqual('http://server/pre/otherPath');