[lld] [lld][WebAssembly] Add `GOT.mem` for `WASM_MEMORY_ADDR_REL_` of Shared Data (PR #104920)

[Sam Clegg via llvm-commits]

sbc100 wrote:

The way this stuff is designed to work is that a given symbol is either accessed via the GOT *or* via base register.

If you are accessing something via `__memory_base` or via `__table_base` then the result is a fixed offset from a dynamic location.

If you are accessing something via a GOT entry then each symbol gets its own global (no offset needed).



https://github.com/llvm/llvm-project/pull/104920