#4313 floor, ceiling, unit_step need simplifications applied to noun forms

[Robert Dodier]

For several basic functions, simplification is applied to both noun and verb forms.

(%i1) ['(sin(1.0)), '(cos(1.0)), '(bessel_j(0, 0)), '(signum(1.0)), '(abs(1.0))];
(%o1)     [0.8414709848078965, 0.5403023058681398, 1, 1.0, 1.0]
(%i2) ['sin(1.0), 'cos(1.0), 'bessel_j(0, 0), 'signum(1.0), 'abs(1.0)];
(%o2)     [0.8414709848078965, 0.5403023058681398, 1, 1.0, 1.0]

But for floor, ceiling, and unit_step, simplification is only applied to verb forms.

(%i3) ['(floor(1.0)), '(ceiling(1.0)), '(unit_step(1.0))];
(%o3)                 [1, 1, 1]
(%i4) ['floor(1.0), 'ceiling(1.0), 'unit_step(1.0)];
(%o4)  [floor(1.0), ceiling(1.0), unit_step(1.0)]

Should assign to the noun forms whatever simplifications are in effect for the corresponding verb forms.