Fix occassional CME in physics tests.

        vararg additionalUpdateMatchers: UpdateMatcher

    ) {

        val updateFrames: UpdateFramesPerProperty<T> = getAnimationUpdateFrames(animator)

        if (!updateFrames.containsKey(property)) {

            error("No frames for given target object and property.")

        }

        // Copy the frames to avoid a ConcurrentModificationException if the animation update

        // listeners attempt to add a new frame while we're verifying these.

        val framesForProperty = ArrayList(updateFrames[property]!!)

        val matchers = ArrayDeque<UpdateMatcher>(

                additionalUpdateMatchers.toList())

        val frameTraceMessage = StringBuilder()

        var curMatcher = firstUpdateMatcher

        // Loop through the updates from the testable animator.

        for (update in updateFrames[property]

                ?: error("No frames for given target object and property.")) {

        for (update in framesForProperty) {

            // Check whether this frame satisfies the current matcher.

            if (curMatcher(update)) {