Add missing constant propogation folder for SNegate, [Logical]Not. Implement additional folding when !(!x) for all ops. This helps for readability of lowered code into SPIR-V. Part of work for #70704
Add missing constant propogation folder for SNegate, [Logical]Not. Implement additional folding when !(!x) for all ops. This helps for readability of lowered code into SPIR-V. Part of work for #70704