perf(Change Detection): remove the usage of getters/setters

- Firefox is 2.4x faster (90 vs 221ms)
- Chrome is 24% slower (15.5 vs 12.5ms)

Chrome is still 5.8x faster than Firefox

modules/change_detection/test/record_range_spec.js

@@ -212,8 +212,8 @@ export function main() {
         record2.disable();
         record3.disable();
 
-        expect(record2.disabled).toBeTruthy();
-        expect(record3.disabled).toBeTruthy();
+        expect(record2.isDisabled()).toBeTruthy();
+        expect(record3.isDisabled()).toBeTruthy();
 
         expect(enabledRecords(rr, recordNames)).toEqual(['record1', 'record4']);
       });