[compiler-rt] [WebAssembly] Define llvm-internal WasmEH tags in compiler-rt (PR #160959)

[Mike Hommey via llvm-commits]

glandium wrote:

CMakeLists.txt says `__cpp_exceptions.S`, but the added file was `__cpp_exception.S`. This breaks building the wasm compiler-rt.

https://github.com/llvm/llvm-project/pull/160959