fix($parse): set null reference properties to undefined

When there is an expression of the form `true && a.b` and where `a == null`, then set
the value of `true && a.b` to `undefined`.

Closes angular#11959

Author: lgalfaso

src/ng/parse.js

@@ -983,6 +983,8 @@ ASTCompiler.prototype = {
             }
           }
           recursionFn(intoId);
+        }, function() {
+          self.assign(intoId, 'undefined');
         });
       }, !!create);
       break;

test/ng/parseSpec.js

@@ -1745,6 +1745,10 @@ describe('parser', function() {
         expect(scope.$eval("0&&2")).toEqual(0 && 2);
         expect(scope.$eval("0||2")).toEqual(0 || 2);
         expect(scope.$eval("0||1&&2")).toEqual(0 || 1 && 2);
+        expect(scope.$eval("true&&a")).toEqual(true && undefined);
+        expect(scope.$eval("true&&a.b")).toEqual(true && undefined);
+        expect(scope.$eval("false||a")).toEqual(false || undefined);
+        expect(scope.$eval("false||a.b")).toEqual(false || undefined);
       });
 
       it('should parse ternary', function() {