RFR 8028433: [TESTBUG] add -XX:+UsePerfData to some sun.management tests

[Jaroslav Bachorik]

Please, review this simple test change.

Issue : https://bugs.openjdk.java.net/browse/JDK-8028433
Webrev: http://cr.openjdk.java.net/~jbachorik/8028433/webrev.00

The tests relying on the availability of the perf counters need to add 
-XX:+UserPerfData jvm arg in order for them to be available on the 
embedded platforms. Additionally, the tests must be run in othervm mode 
- due to the specified jvm arg.

-JB-