RFR(XXS): 8144629: runtime/thread/Fibonacci.java test should ran in othervm mode

[Dmitry Dmitriev]

Hello,

Please review trivial fix for runtime/thread/Fibonacci.java which change 
execution mode to the "othervm" to avoid possible deadlock in jtreg 
agent when uncaught exception is got.

JBS: https://bugs.openjdk.java.net/browse/JDK-8144629
webrev: http://cr.openjdk.java.net/~ddmitriev/8144629/webrev.00/ 
<http://cr.openjdk.java.net/%7Eddmitriev/8144629/webrev.00/>

Dmitry