[llvm] [SLP][REVEC] Make GetMinMaxCost support FixedVectorType when REVEC is enabled. (PR #114946)

[via llvm-commits]

dyung wrote:

Hi @HanKuanChen, the test you modified is failing on at least one upstream bot https://lab.llvm.org/buildbot/#/builders/174/builds/8058. It might have been masked by the previous failure on the bot. Can you take a look?

https://github.com/llvm/llvm-project/pull/114946