[llvm] [RISCV][GISel] Support select G_INSERT_SUBVECTOR (PR #171092)

[Jianjian Guan via llvm-commits]

jacquesguan wrote:

> Looks like you have a failing test

OK now after rebase with https://github.com/llvm/llvm-project/pull/171091.

https://github.com/llvm/llvm-project/pull/171092