RFR: 8274048 IGV: Replace usages of Collections.sort with List.sort call

[Andrey Turbanov]

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

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Commit messages:
 - [PATCH] Replace usages of Collections.sort with List.sort call in IGV

Changes: https://git.openjdk.java.net/jdk/pull/5228/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5228&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8274048
  Stats: 24 lines in 8 files changed: 0 ins; 2 del; 22 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5228.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5228/head:pull/5228

PR: https://git.openjdk.java.net/jdk/pull/5228