RFR: 8274319: Replace usages of Collections.sort with List.sort call in jdk.jfr

[Andrey Turbanov]

Collections.sort is just a wrapper, so it is better to use an instance method directly.

Also Comparator's implementation can be cleaned up with help of static methods in `Comparator` class.
E.g `(u, v) -> Long.compare(v.count, u.count)` can be replaced with `Comparator.comparingLong(v -> v.count)`

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Commit messages:
 - 8274319: Replace usages of Collections.sort with List.sort call in jdk.jfr

Changes: https://git.openjdk.java.net/jdk/pull/5696/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5696&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274319
  Stats: 29 lines in 10 files changed: 1 ins; 10 del; 18 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5696.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5696/head:pull/5696

PR: https://git.openjdk.java.net/jdk/pull/5696