[llvm] [SPARC] Emit a TRUNCATE when combining truncating BSWAP-STOREs (PR #210483)

[Rainer Orth via llvm-commits]

rorth wrote:

I've just tested the patch on `sparcv9-sun-solaris2.11`, both on `main` and on top of LLVM 23.1.0 rc1.  The build works again and testsuite results are back to normal.  Thanks.

https://github.com/llvm/llvm-project/pull/210483