RFR(XS) 8207202: [Graal] compiler/graalunit/CoreTest.java fails

[Tom Rodriguez]

The code for generating the ArrayIndexOutOfBoundsException message from 
the interpreter keeps a bare oop alive across a safepoint resulting in 
an incorrect message or potentially a crash.  To match the other uses of 
note_trap I simply rearranged the code to use it before the safepoint 
and included a message explaining the ordering.

http://cr.openjdk.java.net/~never/8207202/webrev
https://bugs.openjdk.java.net/browse/JDK-8207202