Updated widening logic for scalar case. Simplified Let variable naming.
Updated widening logic for scalar case. Simplified Let variable naming.


Former-commit-id: afeef37d9812b7f98f7824ca4694857c0c4f1061
darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide