fix(ngPattern): Changed pattern to validate against input field value

Set patternDirective validator to test against viewValue instead of
modelValue.

Closes angular#12344, angular#12618

Author: kacecode

src/ng/directive/validators.js

@@ -43,8 +43,8 @@ var patternDirective = function() {
         ctrl.$validate();
       });
 
-      ctrl.$validators.pattern = function(value) {
-        return ctrl.$isEmpty(value) || isUndefined(regexp) || regexp.test(value);
+      ctrl.$validators.pattern = function(modelValue, viewValue) {
+        return ctrl.$isEmpty(viewValue) || isUndefined(regexp) || regexp.test(viewValue);
       };
     }
   };