Wasm ESM integration does not seem to work with import/exporting wasm mutable globals

[sbc100]

It seems to coerce the Wasm globals in the numbers (i.e. snapshots them), which seems to make exporting mutable globals and manipulating them from JS impossible.

[devalgupta404]

@sbc100 I've implemented a fix for issue #25543 The issue occurs in two places:

1. tools/extract_metadata.py - get_global_exports() only stores the numeric value of globals, losing mutability information
2. tools/emscripten.py - create_global_exports() and create_receiving() don't handle mutable globals specially in ESM integration mode

I modified get_global_exports() to store both value and mutability in tools/extract_metadata.py:

tools/emscripten.py - Updated create_global_exports() to skip declaring mutable globals locally in ESM mode (they'll be imported from WASM instead)

Modified create_receiving() to import mutable globals from the WASM module in ESM integration mode

Before raising the PR, I'd like to understand your preferred testing approach

[sbc100]

We do now support exporting mutable globals to JS since I landed #25530.

The issue described in this bug is that there is no way to export mutable globals from Wasm to JS under the ESM integration proposal. I don't think this something that emscripten can solve because its more of spec issue. See https://github.com/WebAssembly/esm-integration/pull/104

[sbc100]

According to https://github.com/emscripten-core/emscripten/issues/25543 it seems like this issue is not something that is possible with the current ESM integration spec.