RFR(S): 8215890: [TESTBUG] jdk/jfr/api/recording/event/TestPeriod.java fails with "period delta too short"

[mikhailo.seledtsov at oracle.com]

Please review this small change. The root cause of the bug was the 
assumption that the events are ordered by
time in the recording, which is not always true. There is no guarantee 
of that in current design. The fix is to order the events of interest by 
time before calculating the deltas.
Also, while running preliminary testing I have noticed that on occasion 
the test will time out. The root cause
is that a test case iteration did not have enough time to record minimum 
number of events. I have added a bit of
extra time intended to fix this problem.

     JBS: https://bugs.openjdk.java.net/browse/JDK-8215890
     Webrev: http://cr.openjdk.java.net/~mseledtsov/8215890.01/
     Testing:
         Ran this test multiple times on Linux-x64, Mac, Win-x64, Sol-Spc
            20 times on each platform - All PASS

Thank you,
Misha