[code-reflection] RFR: Short cut for single method execution

[Paul Sandoz]

This allows us to retain the exact method declaration and simply wrap in a lambda (its like an optimization). The execute method requires the user pass the lookup, otherwise reflective access can fail. We can overload using the public lookup if need be later on.

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Commit messages:
 - Short cut for single method execution

Changes: https://git.openjdk.org/babylon/pull/329/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=329&range=00
  Stats: 198 lines in 2 files changed: 127 ins; 3 del; 68 mod
  Patch: https://git.openjdk.org/babylon/pull/329.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/329/head:pull/329

PR: https://git.openjdk.org/babylon/pull/329