Open-world store-to-load forward optimization for globals

[mkustermann]

This is basically the issue I filed in #8002 - with the extra requirement that this should also work in an open-world setting.

The same reproduction still applies and fails to optimize the global.get + struct.get pattern if optimized via

% wasm-opt --enable-gc --enable-reference-types --enable-multivalue --enable-exception-handling \
     --enable-nontrapping-float-to-int --enable-sign-ext --enable-bulk-memory \
     --enable-threads '--no-inline=*<noInline>*' --traps-never-happen -g \
     -Os \
     bad.wasm -o bad.opt.wasm

From the change in PR #8005 it seems that this works with --gsi which requires --closed-world.

For background: We have some use cases where our compiler emits multiple wasm modules and we'd like to locally optimize each of them. Some simple analysis suggests we'd save 3.5 KB on one of the modules.

[kripken]

Makes sense, fix in #8020