[lworld] RFR: 8231500: [lworld] Merge the experimental bytecode API [v2]

[David Simms]

> * Moved to a single bytecode testing API
> * Cleaned out vbytecodes
> * Cleanup of tests not actually using the API
> * Removed TestNativeClone's API usage since cooking the method handle could no
> longer bypass the verifier's bad access check

David Simms has updated the pull request incrementally with one additional commit since the last revision:

  Review comments applied

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Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/279/files
  - new: https://git.openjdk.java.net/valhalla/pull/279/files/96f29c0f..c7d9c288

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=279&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=279&range=00-01

  Stats: 20 lines in 8 files changed: 0 ins; 4 del; 16 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/279.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/279/head:pull/279

PR: https://git.openjdk.java.net/valhalla/pull/279