[Wasm R2R] directly call the async resumption stub

[AndyAyersMS]

In the initial runtime async PR for Wasm (#131167) we use the general call mechanism for invoking the resumption stub. On other platforms we emit a direct call to ensure that the resumption stub comes from a matching IL version of the method.

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[AndyAyersMS]

Not sure if we'll get to this in .NET 11.