Fixes#18029.
There are ways to load assemblies that the search hook has no way of intercepting,
and handling itself. Such as loading from a byte[] in C# code.
We now handle these cases with a fallback assembly_load_hook,
to avoid crashes when this is indeed done.
- Setup runtime main args during initialization. This must be done manually by embedders who do not call mono_runtime_run_main. Fixes NullReferenceException in System.Environment.
- Continue to search the assembly in the rest of the search locations if loading it from one of them failed.
The heuristic whether we're in the project manager inside GDMono
didn't work if the project manager was launched by not having any path
to run.
This is fixed now by making a Main::is_project_manager().
It's going to be called anyway after `mono_domain_finalize`.
This also prevents crashes, since the MessageQueue singleton could already be freed at this point (see: #15702).
- Bundle with mscorlib.dll to avoid compatibilities issues
- Add build option 'mono_assemblies_output_dir' to specify the output directory where the assemblies will be copied to. '#bin' by default.
- Sometimes `StackFrame.GetMethod()` returns null (e.g.: latest frame of a `MissingMethodException`). Still not sure what to do with that frame (maybe skip it), but at least it no longer fails.
- Skip `CSharpLanguage::debug_get_current_stack_info()` if an error is printed from `GDMonoUtils::update_corlib_cache()`.
- Fix crash when calling `GDMonoUtils::print_unhandled_exception(exc)` if there is no ScriptDebugger attached.
Using `misc/scripts/fix_headers.py` on all Godot files.
Some missing header guards were added, and the header inclusion order
was fixed in the Bullet module.
- alloc_language_binding: Use strong GC handle as well for references. Fixes#15138
- Set the native instance field of Godot.Object to IntPtr.Zero when it's freed.
- Create weak handles without tracking resurrection (that was causing trouble). This means we have to call notification predelete before queueing a native Object for deletion, and use the MonoObject* passed by the finalizer because the weak GC handle target will return NULL at this point.
