Let WasmTy differentiate between passing ownership into Wasm vs a borrow

[fitzgen]

Only matters for reference types. But if we know the call is borrowing a reference type that will outlive the call, we don't need to add it into the activations table because the borrow checker already ensures it will live long enough.

Currently only Func::{wrap,get} will pass by value (and therefore need the activations table) while Func::call will pass borrows (and therefore we know the reference will outlive the call, and it doesn't need to go into the table).

See also bytecodealliance/wasmtime-dotnet#27 (comment)

[github-actions]

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