[llvm] [RISCV] Override default sched policy (PR #115445)

[Min-Yih Hsu via llvm-commits]

mshockwave wrote:

> This PR will only enable bidirectional scheduling and tracking register pressure. And `ShouldTrackLaneMasks`/`DisableLatencyHeuristic` will be follow-ups (need more inputs).

Agree. Could you update the patch description to reflect this change?

https://github.com/llvm/llvm-project/pull/115445