RFR: 6872: Add butterfly/sandwich view to JMC

Mon Dec 8 16:41:35 UTC 2025

This PR adds a butterfly (aka sandwich) view to JMC, showing all the callers and callees for a selected method. 

<img width="2548" height="1224" alt="buttefly" src="https://github.com/user-attachments/assets/ad3d33d8-944b-49d6-be98-62444f11da93" />

Also fixes annoying spelling error.

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Commit messages:
 - Copyright fix
 - 6872: Add butterfly/sandwich view to JMC

Changes: https://git.openjdk.org/jmc/pull/693/files
  Webrev: https://webrevs.openjdk.org/?repo=jmc&pr=693&range=00
  Issue: https://bugs.openjdk.org/browse/JMC-6872
  Stats: 890 lines in 18 files changed: 859 ins; 21 del; 10 mod
  Patch: https://git.openjdk.org/jmc/pull/693.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/693/head:pull/693

PR: https://git.openjdk.org/jmc/pull/693