JS: Skip runtime unit checks for expressions when safe to do so
JS: Skip runtime unit checks for expressions when safe to do so

Signed-off-by: Matt Chudleigh <0ca390ed93f516590d05286882efa52bb3b35616@gmail.com>

jaamsim/jaamsim,jaamsim/jaamsim,jaamsim/jaamsim,jaamsim/jaamsim