RFR (s) 8055145: [TESTBUG] runtime/7158988/FieldMonitor.java fails with VMDisconnectedException

[Coleen Phillimore]

Summary: Exclude this test on JPRT and make it trivially pass if it gets 
a disconnected exception (which seems rare)

open webrev at http://cr.openjdk.java.net/~coleenp/8055145/
bug link https://bugs.openjdk.java.net/browse/JDK-8055145

Ran JPRT job.

Thanks,
Coleen