In [gc.go](https://cs.opensource.google/go/go/+/master:src/cmd/go/internal/work/gc.go;l=75?q=src%2Fcmd%2Fgo%2Finternal%2Fwork%2Fgc.go&ss=go%2Fgo), we perform a _allowedVersion_ check prior to passing -lang to the compiler but we are interested in the cases when this check would fail. Requires more investigation. CC: @matloob
