perf(isArray): use native Array.isArray

Request Type: perf

How to reproduce: 

Component(s): misc core

Impact: small

Complexity: small

This issue is related to: 

**Detailed Description:**



**Other Comments:**

see benchmark: http://jsperf.com/isarray-performance
`return Array.isArray;` --- this is a static and doesn't depend on being attached to the `Array` constructor