RFR: Minor fixes, microoptimizations and cleanup

Tue Oct 6 14:56:20 UTC 2020

I already signed Oracle contributor agreement and I'm JCP member so my changes can be accepted.

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Commit messages:
 - FieldLayout: Extract classShortName()
 - samples: @Contended also may have a value
 - Fix incorrect usage of Assert.assertNotSame() and use assertNotEquals() instead
 - HeapDumpStats: create sorted variable by copying constructor
 - Migrate from junit.framework.Assert to org.junit.Assert
 - README.md: use https for link

Changes: https://git.openjdk.java.net/jol/pull/3/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jol&pr=3&range=00
  Stats: 30 lines in 11 files changed: 17 ins; 2 del; 11 mod
  Patch: https://git.openjdk.java.net/jol/pull/3.diff
  Fetch: git fetch https://git.openjdk.java.net/jol pull/3/head:pull/3

PR: https://git.openjdk.java.net/jol/pull/3