[llvm] [InlineCost] Correct the default branch cost for the switch statement (PR #85160)

[Quentin Dian via llvm-commits]

DianQK wrote:

> Ping for review :) I am happy with the performance data on RISC-V. This patch saves ~8% instructions in some benchmarks.

Could you test from d69f4bc19bc04ed0b3c056938b711ea7d7712ef0 to 01838cc6223ceb3c1e0f675865d30aea32db3f71? 58622ef6755a02f97e5127bea29ed5b8812fe25e is just a revert commit.

https://github.com/llvm/llvm-project/pull/85160