[clang] [llvm] Reland "[RISCV] Support RISCV BitInt larger than 128 (#175515)" (PR #190188)

[Piyou Chen via cfe-commits]

BeMg wrote:

> Is there a test for #176637 in here to show that it works now?

Added by https://github.com/llvm/llvm-project/pull/190188/commits/9cdc7d4256df3bc876a009b574df72a87a76789b

https://github.com/llvm/llvm-project/pull/190188