CB-7444 Fixes XHR callback failure when requested file doesn't exists

(cherry picked from commit d2aeff23032f5d3705cb262d6d7a3e30e6f2b049)
CB-7843 Fixes angular routing on WP8

(cherry picked from commit e693d147b87641fcc2f341dbea7bc7c73d14f9e1)
CB-7892 XHR to local files poly should only load/run once

(cherry picked from commit 6bb3fc38a4d67cf378e1b11839c4af327ebfccd5)
Adding fixes to XHRHelper class to successfully work with Angular JS.

- Cordova RTC work item number: 60654
- Apache Cordova Jira issue:
https://issues.apache.org/jira/browse/CB-7444,
https://issues.apache.org/jira/browse/CB-7843,
https://issues.apache.org/jira/browse/CB-7892
- Markmail or Google Group reference: n/a
- Product PMR: 65567,650,758
- APAR: PI31953 - Item 60655
- Cherry-pick: d2aeff23032f5d3705cb262d6d7a3e30e6f2b049,
e693d147b87641fcc2f341dbea7bc7c73d14f9e1,
6bb3fc38a4d67cf378e1b11839c4af327ebfccd5
- Description: Main issue is that the window.__XHRShimAliases object
gets recreated when window location changes, causing that callbacks for
XHR calls are never getting received.
A condition was added to define if the object is already present, and
avoid unnecessary recreation. Another fix was added to properly process
a callback when the file doesn't exists.
The last one was added to fix an angular use case, to avoid reload on
InjectScript Method when the url is changed.