spectest: ensure compiled functions can outlive module

[ncruces]

Tentative fix for #2039 for the compiler, not wazevo.

In linking.wast we have:

• a module A that exports its memory and table
• a module B that imports both
  • it initializes the (shared) memory, and
  • it initializes the (shared) table, setting entry zero to one of its functions
  • then it fails while running main

The test then verifies that initializing the memory and the table both succeeded before main failed. It does so by reading from the memory, and indirect calling the function in the table.

Both the memory and table are owned by A, so still exist. But the function, or rather the compiled code (and mmaped memory) for the function is/was owned by B and can be GCed, because we SetFinalizer on an object owned by B.

This change makes it so that the finalizer is set on the compiledCode rather than on the compiledModule. Since the resolved function import is a function, and that owns a compiledFunction, which owns the compiledCode, this should fix the issue.

[achille-roussel]

The change looks good, do you want to merge this in independently of #2102 ?

[ncruces]

The change looks good, do you want to merge this in independently of #2102 ?

I'd reviewed a previous version of that, and (I guess because the title was not updated) totally missed the progress.
Then went on and duplicate all the work. 🤦

Happy to shelve this.

[ncruces]

Everything is already in #2102.