gczeal(0);
let objects = [{}, {}, {}];
blackRoot()[0] = objects[0];
grayRoot()[0] = objects[1];
addMarkObservers(objects);
objects = undefined;
gc();
assertEq(getMarks()[0], "black");
assertEq(getMarks()[1], "gray");
assertEq(getMarks()[2], "dead");
