Emit custom modifiers into native layout metadata

[MichalStrehovsky]

When we started generating custom modifiers into metadata format to support new function pointer APIs in #85504, we should have also added it to native layout format. We currently have a mismatch. It's likely generic virtual dispatch and LDTOKEN is going to be wrong if we're in a situation where two method signatures only differ by modifiers.

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Issue Details

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When we started generating custom modifiers into metadata format to support new function pointer APIs in #85504, we should have also added it to native layout format. We currently have a mismatch. It's likely generic virtual dispatch and LDTOKEN is going to be wrong if we're in a situation where two method signatures only differ by modifiers.

Author:	MichalStrehovsky
Assignees:	-
Labels:	area-NativeAOT-coreclr
Milestone:	9.0.0