[llvm] [AMDGPU] Add amdgpu-sw-lower-lds pass to NPM codegen addIRPasses. (PR #124102)

[via llvm-commits]

skc7 wrote:

> We don't really need to test the new and old PM in every single test of the pass, you can drop most of the test changes or migrate most of them to only use the new pm

Dropped the changes as suggested. PR has now only one basic test which has both the cases tested.

https://github.com/llvm/llvm-project/pull/124102