[llvm] [AArch64][GlobalISel] Reland Make G_DUP immediate 32-bits or larger (#96780) (PR #99014)

[David Green via llvm-commits]

davemgreen wrote:

Looking at #96780 it used a CustomMappingID and had an extra assert for smaller types. They are probably worth bringing into this recommit too.

https://github.com/llvm/llvm-project/pull/99014