[lworld] RFR: [lworld] small reflection implementation clean up

[Mandy Chung]

Post-merge clean up on reflection implementation.

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Commit messages:
 - [lworld] misc reflection clean up
 - Merge
 - Post-merge adjustment in DirectMethodHandle

Changes: https://git.openjdk.java.net/valhalla/pull/93/files
 Webrev: https://webrevs.openjdk.java.net/valhalla/93/webrev.00
  Stats: 116 lines in 7 files changed: 20 ins; 61 del; 35 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/93.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/93/head:pull/93

PR: https://git.openjdk.java.net/valhalla/pull/93