[browser][MT] use code generator to get JSExport methods/ reduce reflection

[pavelsavara]

• no reflection or move reflection to C# of BindManagedFunctionImpl
• Interop.Runtime.BindCSFunction should be only passing MethodHandle to JS
• drop mono_wasm_assembly_load, mono_wasm_assembly_find_class, mono_wasm_runtime_run_module_cctor, mono_wasm_assembly_find_method
• don't breach GC barrier
• Add unit tests to src\mono\wasm\Wasm.Build.Tests\MainWithArgsTests.cs for each combination of Main method name, signature and visibility.

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Issue Details

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• no reflection or move reflection to C# of BindManagedFunctionImpl
• Interop.Runtime.BindCSFunction should be only passing MethodHandle to JS
• drop mono_wasm_assembly_load, mono_wasm_assembly_find_class, mono_wasm_runtime_run_module_cctor, mono_wasm_assembly_find_method
• don't breach GC barrier

Author:	pavelsavara
Assignees:	pavelsavara
Labels:	arch-wasm, area-System.Runtime.InteropServices.JavaScript, os-browser
Milestone:	9.0.0

[maxkatz6]

I would assume this is also necessary for NativeAOT-LLVM compatibility dotnet/runtimelab#2626