S3L_array_scalar_op2 applies a binary operation to each element of an S3L array that involves the element and a scalar.
op determines which operation will be performed. It can be one of:
S3L_OP_MULT - pointwise multiplication.
S3L_OP_DIV - pointwise division.
S3L_OP_PLUS - pointwise addition.
S3L_OP_MINUS - pointwise subtraction.
S3L_OP_ASSIGN - assignment.