Run less varargs tests (emscripten-core#20797)

Arguably we maybe don't need to test them even in wasm2js, as the wasm backend
lowers them to something that the wasm2js should not have any special handling for,
but I think it's worth keeping that testing around to be safe.

Also enable test_nested_struct_varargs which has been disabled since the beginning
of time, because it failed in fastcomp, but it has passed in the wasm backend (since
forever, I suspect, as the issue was legalization, which was never a problem for the
wasm backend).

[wasm64] Fix emmalloc+verbose under wasm64 (emscripten-core#20654)

Remove CMakeLists.txt from LLVM libraries (emscripten-core#20614)

We don't use their CMake system, and we have already removed several of
`CMakeLists.txt`, but not all. To be consistent, this removes the
remaining ones. Also updates `update_***.py` scripts accordingly so that
they are not copied again.

embind: Fix tsgen when embind is linked multiple times. (emscripten-c…

…ore#20403)

When embind was linked multiple times the js file would be included
multiple times and regular embind library would override the instrumented
version causing an empty TS file to be created.

embind: Ignore more options during TS generation and force node envir…

…onment. (emscripten-core#20242)

All of these options can potentially conflict with TS generation.

Add libunwind to update scripts (emscripten-core#20091)

- Add libunwind to `push_llvm_changes.py`
- Add `update_libunwind.py`

Add CMake note to debug information section (emscripten-core#19879)

Use dedicated API to know if fullscreen/pointerlock can be requested (e…

…mscripten-core#19758)

Fullscreen can be requested during transient activation
not just while handling an input event, so check for that
on browsers that support it.

Fix regression with Safari and EXPORT_NAME (emscripten-core#19656)

Fixes: emscripten-core#18357

WasmFS JS API: Implement read (emscripten-core#19504)