[clang] [llvm] [dwarf] make dwarf fission compatible with RISCV relaxations (PR #164128)

[via llvm-commits]

daniilavdeev wrote:

Split into: https://github.com/llvm/llvm-project/pull/166597, https://github.com/llvm/llvm-project/pull/164813, https://github.com/llvm/llvm-project/pull/169653

https://github.com/llvm/llvm-project/pull/164128