RFR: 8251843: jfr/tool/TestPrintJSON.java fails intermittently [v4]

[Erik Gahlin]

> The 'jfr' tool can print events in JSON and XML and the result is verified by reading the same file using the jdk.jfr.consumer API. The method RecordedEvent::getEndTime() exposes timestamps with nano-precision (java.time.Instant), while the tool sorts them according to ticks.  It is believed that  events with different ticks timestamp in some circumstances may get the same nano-precision timestamp. This leads to events not arriving in the same order and the test fails.
> 
> Fix is to sort events in the test by ticks as well

Erik Gahlin has updated the pull request incrementally with one additional commit since the last revision:

  Remove unused imports

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/1589/files
  - new: https://git.openjdk.java.net/jdk/pull/1589/files/584f4713..053e3b4c

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=1589&range=03
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=1589&range=02-03

  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1589.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1589/head:pull/1589

PR: https://git.openjdk.java.net/jdk/pull/1589