[release/7.0-rc1] [MONO] Make mono_marshal_ilgen_init a public MONO_API function again

[github-actions]

Backport of #74658 to release/7.0-rc1

/cc @lewing @naricc

Customer Impact

Testing

Risk

IMPORTANT: Is this backport for a servicing release? If so and this change touches code that ships in a NuGet package, please make certain that you have added any necessary package authoring and gotten it explicitly reviewed.

[lewing]

We have a workaround in xamarin/xamarin-macios#15788 so if that lands this can be retargeted to release/7.0

[dalexsoto]

@lewing not sure what will be faster, our CI started going 🍌s today :( so I would say if you can keep the train going on this one as a fail safe might be better

[lewing]

@lewing not sure what will be faster, our CI started going 🍌s today :( so I would say if you can keep the train going on this one as a fail safe might be better

I'm not stopping it but taking a new runtime package will put schedules at risk

[dalexsoto]

@lewing Looks like we need this PR after all see:

xamarin/xamarin-macios#15788 (comment)

I'm now a little bit concerned that this was the wrong fix.
When using the interpreter you link the mono-ilgen.a library and I think in that case the call to mono_marshal_ilgen_init has to stay. So maybe we need the runtime fix #74658 after all

https://github.com/xamarin/xamarin-macios/blob/028afc2eabb4af8b7087ebd7f9a6cf6f66ec96b8/tools/mtouch/Target.mtouch.cs#L1530

[carlossanlop]

@mmitche do we still have runway to get this merged to RC1?

[lewing]

can't merge this as is, it breaks wasm. alternate fix staged in #74675 while we keep working on this