[code-reflection] RFR: Move Patterns to tests and examples.

[Paul Sandoz]

Move Patterns to tests and examples.

Consolidate expressions elimination test under auto-diff test.

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Commit messages:
 - Move Patterns to tests and examples.

Changes: https://git.openjdk.org/babylon/pull/836/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=836&range=00
  Stats: 149 lines in 6 files changed: 6 ins; 116 del; 27 mod
  Patch: https://git.openjdk.org/babylon/pull/836.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/836/head:pull/836

PR: https://git.openjdk.org/babylon/pull/836