RFR(S): 8211932: [ppc][testbug] runtime/jni/terminatedThread/TestTerminatedThread.java fails as threads don't terminate immediately

[Lindenmaier, Goetz]

Hi,

On ppc, one still sees increasing thread cpu times after a thread has joined. 
This makes TestTerminatedThread fail.

This change gives the check a few seconds to wait until the thread disappears.
Please review.
http://cr.openjdk.java.net/~goetz/wr18/8211931-terminatedThrd/01/test/hotspot/jtreg/runtime/jni/terminatedThread/TestTerminatedThread.java.udiff.html

Best regards,
  Goetz.