[code-reflection] RFR: Use JUnit instead of TestNG

[Mourad Abbay]

Use JUnit instead of TestNG

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Commit messages:
 - Use junit instead of testng

Changes: https://git.openjdk.org/babylon/pull/566/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=566&range=00
  Stats: 79 lines in 8 files changed: 19 ins; 8 del; 52 mod
  Patch: https://git.openjdk.org/babylon/pull/566.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/566/head:pull/566

PR: https://git.openjdk.org/babylon/pull/566