review: Build should fail fast with unsupported OS/ARCH

[David Hill]

thanks to Jyri's email, I have a simple fix to fail quickly and with a understandable error message.

jbs: https://bugs.openjdk.java.net/browse/JDK-8163196
simple diff inside jbs


-- 
David Hill<David.Hill at Oracle.com>
Java Embedded Development

"A man's feet should be planted in his country, but his eyes should survey the world."
-- George Santayana (1863 - 1952)