fix(Scope): don't clear the phase when an exception is thrown from asyncQueue or watch

If we clear it here, then any other watch or async task could start a new digest.

src/ng/rootScope.js

@@ -699,7 +699,6 @@ function $RootScopeProvider(){
               asyncTask = asyncQueue.shift();
               asyncTask.scope.$eval(asyncTask.expression);
             } catch (e) {
-              clearPhase();
               $exceptionHandler(e);
             }
             lastDirtyWatch = null;
@@ -742,7 +741,6 @@ function $RootScopeProvider(){
                     }
                   }
                 } catch (e) {
-                  clearPhase();
                   $exceptionHandler(e);
                 }
               }

test/ng/rootScopeSpec.js

@@ -176,15 +176,6 @@ describe('Scope', function() {
       });
     });
 
-    it('should clear phase if an exception interrupt $digest cycle', function() {
-      inject(function($rootScope) {
-        $rootScope.$watch('a', function() {throw new Error('abc');});
-        $rootScope.a = 1;
-        try { $rootScope.$digest(); } catch(e) { }
-        expect($rootScope.$$phase).toBeNull();
-      });
-    });
-
 
     it('should fire watches in order of addition', inject(function($rootScope) {
       // this is not an external guarantee, just our own sanity