Some test runs fail during the code generation step, when WAVM complaints that it can't find a missing CPU feature:

Target X86 CPU (generic) does not support SSE 4.1, which WAVM requires for WebAssembly SIMD code.

This issue is related: WAVM/WAVM#312

List of machines that trigger the problem:

There's a similar thread on the bytecodealliance zulip chat. Then it was not a false positive like in the WAMR issue, rather a very old machine. I personally don't think any of the machines in GHA are so old not to have SSE 4.1, so it may be an issue with our LLVM installation being (potentially) too old. Hopefully when we move to LLVM 13 this problem goes away.