[llvm] [WebAssembly] Implement lowering calls through funcref to call_ref when available (PR #162227)

[Demetrius Kanios via llvm-commits]

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QuantumSegfault wrote:

I wasn't sure what the best spot was for the new `return_call_ref` test. It seemed natural to include it here, but then that requires conditional compilation to keep it from erroring out when gc isn't available. Is that a problem?

https://github.com/llvm/llvm-project/pull/162227