After 0d4a709bb8 LLVM becomes more clever and turns `@wider_reduce_loop` into an alias: https://buildkite.com/llvm-project/rust-llvm-integrate-prototype/builds/17806#0186da6b-582c-46bf-a227-1565fa0859ac/743-766 This adapts the test to prevent this.
0d4a709bb8