[jit] Fix signed division by power of 2 optimization.
[jit] Move optimizations from cprop to decompose.

Moved optimizations for signed division by power of two and unsigned division and remainder by power of two.
[jit] Replace unsigned division by constants with multiplication, additions and shifts for better performance.
[jit] Replace signed division by constants with multiplication, additions and shifts for better performance.
Add test for constant division.