[llvm] [llvm][mc][riscv] MC support of T-Head vector extension (xtheadvector) (PR #84447)

[Alex Bradbury via llvm-commits]

asb wrote:

Hi @kata-ark, welcome to the LLVM project and thank you for posting your first PR.

I'm afraid I have to raise a pretty important issue here - you note that you've directly ported a gas test case as part of your work. Due to [LLVM's copyright and license policy](https://llvm.org/docs/DeveloperPolicy.html#copyright-license-patents) this isn't something that can be accepted due to GNU as source code and tests being under a different license. Please create original MC layer tests that are not adapted/copied from GNU.

https://github.com/llvm/llvm-project/pull/84447