Add CreateDelegatePointer for PROC and FARPROC

[wherewhere]

Is your feature request related to a problem? Please describe.

For now, we have CreateDelegate to create delegate from PROC and FARPROC. But when the delegate has generated to a struct for delegate*, it cannot work.

Describe the solution you'd like

Add a CreateDelegatePointer method for PROC and FARPROC, such as:

[MethodImpl(MethodImplOptions.AggressiveInlining)]
internal TDelegate CreateDelegatePointer<TDelegate>() where T : unmanaged => Unsafe.As<PROC, T>(ref this.Value);

Describe alternatives you've considered

For now, we can create an extension to use it:

JClass mainClass = env->functions->FindClass.CreateDelegatePointer<FindClass>().Value(env, "java/lang/String"u8.AsPCSTR());

file static class Extensions
{
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static PCSTR AsPCSTR(this scoped in ReadOnlySpan<byte> data) => Unsafe.As<ReadOnlySpan<byte>, PCSTR>(ref Unsafe.AsRef(in data));

    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public static TDelegate CreateDelegatePointer<TDelegate>(this PROC function) where T : unmanaged => Unsafe.As<PROC, T>(ref function);
}

Additional context
#1629

[jevansaks]

I don't understand, what does "FindClass" look like in this definition? And which generated version of PROC are you using? Is this the AOT compatible generated code or is PROC the managed delegate?

[wherewhere]

[global::System.CodeDom.Compiler.GeneratedCode("Microsoft.Windows.CsWin32", "0.3.269+368685089b.RR")]
internal unsafe readonly struct FindClass
{
    public readonly delegate *unmanaged[Stdcall]<global::Java.Runtime.Native.JNIEnv*,global::Windows.Win32.Foundation.PCSTR,winmdroot.Runtime.JClass> Value;

    public FindClass(delegate *unmanaged[Stdcall]<global::Java.Runtime.Native.JNIEnv*,global::Windows.Win32.Foundation.PCSTR,winmdroot.Runtime.JClass>value) => Value = value;

    public static FindClass Null => default;

    public bool IsNull => Value is null;

    public static implicit operator FindClass(delegate *unmanaged[Stdcall]<global::Java.Runtime.Native.JNIEnv*,global::Windows.Win32.Foundation.PCSTR,winmdroot.Runtime.JClass>value) => new FindClass(value);

    public static implicit operator delegate *unmanaged[Stdcall]<global::Java.Runtime.Native.JNIEnv*,global::Windows.Win32.Foundation.PCSTR,winmdroot.Runtime.JClass>(FindClass value) => value.Value;
}

You can see here JNITest.zip