Revert "Silence -Wunused-parameter warnings in Unwind-wasm.c" (#175776)
Reverts llvm/llvm-project#125412
See the discussion in #125412 for why this is necessary. The summary is
that:
- Eliding arguments is the C23 extension, but libunwind builds its C
files with `-std=c99`, so this change broke the build.
- `-Wno-unused-parameter` is part of the build for libunwind, so the
codebase does allow them.