WebSocket patching fails on Safari 7.0 for onopen, onmessage, onclose, onerror properties

[IgorMinar]

When zone detects that we can't patch prototype descriptors, we call patchWebSocketProperties which tries to patch onmessage and friends via descriptors on the instance. This works in Chrome <43 but not in Safari 7.0 where even instance descriptors are not configurable.

Potential fix would be to return a proxy object similar to how patchClass works and intercept all of the property getters and setters via the proxy.

[IgorMinar]

I should also mention that this is not a problem on Safari 7.1 where instance descriptors are configurable. However SauceLabs only provides us with Safari 7.0 and Safari 8.0, not Safari 7.1