(urgent) RFR: JDK-8154292: jdk9-dev: All SE builds failed on 2016-04-14

[Erik Joelsson]

The change to start building the jtreg failure handler introduced a 
required build dependency on jtreg to be able to build a test-image. 
That's wasn't intentional. It should be possible to build the tests 
without having jtreg available. This patch adds a configure arg: 
"--enable-jtreg-failure-handler" which controls if the failure handler 
should be built. It can be true, false or auto, the default is auto. In 
auto mode, the failure handler is built if jtreg is available. When 
true, missing jtreg becomes an error. When false, the build simply skips 
building the failure handler.

I also added --enable-jtreg-failure-handler to the default jib configure 
arguments to enforce building with it in Oracle official builds. Jib is 
already providing jtreg anyway.

Bug: https://bugs.openjdk.java.net/browse/JDK-8154292
Webrev: http://cr.openjdk.java.net/~erikj/8154292/webrev.top.01/

/Erik