RFR: JDK-8173476: Provide lldb from devkit when running tests on macosx

[Erik Joelsson]

When running tests on Macosx, the failurehandle will attempt to use lldb 
to create dumps on timeouts. This logic requires an lldb that isn't too 
old. In our lab we have several instances of too old lldb on the 
machines. To fix this, we can add lldb from the devkit to the path when 
running tests, through Jib.

The patch also corrects the path added by the bootjdk to actually add 
the bin dir on not the JAVA_HOME dir.

Bug: https://bugs.openjdk.java.net/browse/JDK-8173476

Webrev: http://cr.openjdk.java.net/~erikj/8173476/webrev.01/

/Erik