[llvm] [AArch64] Add Ampere1B scheduling/pipeline model (PR #81341)

[David Green via llvm-commits]

davemgreen wrote:

Also -We have found the tests like llvm/test/tools/llvm-mca/AArch64/Neoverse/N1-basic-instructions.s very useful in the past for visualizing the details in the model and making sure all the values are complete. It doesn't look like a similar test was added for the Ampere1, but you might find it useful to add some like it in this case.

https://github.com/llvm/llvm-project/pull/81341