getRecordIndexSlow = function(map, recordKey) {
		// We have to iterate through our Map structure because `recordKey` is non-primitive and not extensible
		for (var i = 0; i < map._keys.length; i++) {
			var _recordKey = map._keys[i];
			if (_recordKey !== undefMarker && SameValueZero(_recordKey, recordKey)) {
				return i;
			}
		}
		return false;
	}
getRecordIndexSlow()
Alternative (and slower) function to `getRecordIndex()`.  Necessary for looking up non-extensible object keys.
@param {Map} map - Map structure 
@param {string|number|function|object} recordKey - Record key to normalize to string accessor for hash map
@returns {number|false} - Returns either a index to access map._keys and map._values, or false if not found