code: function getHandler(x) {
  			if(isPromise(x)) {
  				return x._handler.join();
  			}
  			return maybeThenable(x) ? getHandlerUntrusted(x) : new Fulfilled(x);
  		}
docs: Promise internals Below this, everything is @private 
  Get an appropriate handler for x, without checking for cycles
  @param {*} x
  @returns {object} handler