LibJSGCVerifier: Complain about malloc-backed containers of GC pointers on the stack

[awesomekling]

Putting e.g a Vector<JS::GCPtr<JS::Object>> on the stack is not safe, as Vector is backed by malloc memory.

Consequently, it's also inappropriate as a function return type.

We should complain about this, so the user can switch to using MarkedVector<JS::GCPtr<JS::Object>> or at least Vector<JS::Handle<JS::Object>>.

We need to do this for all malloc-backed containers, but for simplicity let's say: Vector, HashMap, HashTable, and Queue.

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[TomasBorquez]

Hey I would like to take this but i'm not sure what you mean with "complain", do you mean a compile-time error that blocks the build if such patterns are detected, or a compile time warning that notifies the developer of the unsafe usage without stopping the build? I am considering using static_assert for errors or a custom type trait with a [[deprecated]] attribute for warnings