module: rework of memory management in `vm` APIs with the `importModuleDynamically` option
This PR (hopefully) fixes a bunch of memory leaks & use-after-free surrounding vm.Script, vm.compileFunction, vm.SyntheticModule and vm.SourceTextModule when dynamic import is used (see the issues referenced below) and makes it possible for people to upgrade from older versions of Node.js.
This cannot land as-is on v20.x as it depends on https://github.com/nodejs/node/pull/49491 and https://github.com/nodejs/node/pull/49419 which break the ABI on v20x. We need a special Node.js v20-only extension to the V8 API for this to work without breaking the ABI.
module: use symbol in WeakMap to manage host defined options
Previously when managing the importModuleDynamically callback of vm.compileFunction(), we use an ID number as the host defined option and maintain a per-Environment ID -> CompiledFnEntry map to retain the top-level referrer function returned by vm.compileFunction() in order to pass it back to the callback, but it would leak because with how we used v8::Persistent to maintain this reference, V8 would not be able to understand the cycle and would just think that the CompiledFnEntry was supposed to live forever. We made an attempt to make that reference known to V8 by making the CompiledFnEntry weak and using a private symbol to make CompiledFnEntry strongly references the top-level referrer function in https://github.com/nodejs/node/pull/46785, but that turned out to be unsound, because the there's no guarantee that the top-level function must be alive while import() can still be initiated from that function, since V8 could discard the top-level function and only keep inner functions alive, so relying on the top-level function to keep the CompiledFnEntry alive could result in use-after-free which caused a revert of that fix.
With this patch we use a symbol in the host defined options instead of a number, because with the stage-3 symbol-as-weakmap-keys proposal we could directly use that symbol to keep the referrer alive using a WeakMap. As a bonus this also keeps the other kinds of referrers alive as long as import() can still be initiated from that Script/Module, so this also fixes the long-standing crash caused by vm.Script being GC'ed too early when its importModuleDynamically callback still needs it.
module: fix leak of vm.SyntheticModule
Previously we maintain a strong persistent reference to the ModuleWrap to retrieve the ID-to-ModuleWrap mapping from the HostImportModuleDynamicallyCallback using the number ID stored in the host-defined options. As a result the ModuleWrap would be kept alive until the Environment is shut down, which would be a leak for user code. With the new symbol-based host-defined option we can just get the ModuleWrap from the JS-land WeakMap so there's now no need to maintain this strong reference. This would at least fix the leak for vm.SyntheticModule. vm.SourceTextModule is still leaking due to the strong persistent reference to the v8::Module.
module: fix the leak in SourceTextModule and ContextifySript
Replace the persistent handles to v8::Module and v8::UnboundScript with an internal reference that V8's GC is aware of to fix the leaks.
Refs: https://github.com/nodejs/node/issues/44211 Refs: https://github.com/nodejs/node/issues/42080 Refs: https://github.com/nodejs/node/issues/47096 Refs: https://github.com/nodejs/node/issues/43205 Refs: https://github.com/nodejs/node/issues/38695