Summary:
event-target-shim versions before 1.1.0 do not support taking an array for `EventTarget`. react-native requires `^1.0.5`, so this fixes compatibility with those earlier versions.
**Test Plan:** ran WebSocket UIExplorer example with earlier version of event-target-shim.
Closes https://github.com/facebook/react-native/pull/7261
Differential Revision: D3230881
Pulled By: martinbigio
fb-gh-sync-id: 6a22d58841a4b401a200fece64d13a70043fb09a
fbshipit-source-id: 6a22d58841a4b401a200fece64d13a70043fb09a