function isSubPixelRoundingRuleUnknown(value) {
    return value !== $.SUBPIXEL_ROUNDING_OCCURRENCES.ALWAYS &&
        value !== $.SUBPIXEL_ROUNDING_OCCURRENCES.ONLY_AT_REST &&
        value !== $.SUBPIXEL_ROUNDING_OCCURRENCES.NEVER;
}
Checks whether the input value is an invalid subpixel rounding enum value.
@private

@param {SUBPIXEL_ROUNDING_OCCURRENCES} value - The subpixel rounding enum value to check.
@returns {Boolean} Returns true if the input value is none of the expected
{@link SUBPIXEL_ROUNDING_OCCURRENCES.ALWAYS}, {@link SUBPIXEL_ROUNDING_OCCURRENCES.ONLY_AT_REST} or {@link SUBPIXEL_ROUNDING_OCCURRENCES.NEVER} value.