cmd/go: check for another GCC error message

cmd/go: check for another GCC error message

    GCC always recognizes the -fsplit-stack option, but then tests whether
    it is supported by the selected target. If not, it reports
        cc1: error: ‘-fsplit-stack’ is not supported by this compiler configuration
    Check for that error message when deciding whether a compiler option works.

    Reviewed-on: https://go-review.googlesource.com/87137

From-SVN: r256433