[WebAssembly] Upstream misc. EH changes (#92990)

This upstreams more recent, mostly EH changes from libcxx and libcxxabi:
- `__cxa_init_primary_exception`-related changes made when updating to
LLVM 18.1.2 (https://github.com/emscripten-core/emscripten/pull/21638)
- Removes ctype macros
(https://github.com/emscripten-core/emscripten/pull/20960)
- Guard destructor changes with `__wasm__`
(https://github.com/emscripten-core/emscripten/pull/21974)

NOKEYCHECK=True
GitOrigin-RevId: 271eb0686b7b0f9d2e016751399b948ccbbe7925
2 files changed