[code-reflection] RFR: Refine support for captured values.

[Paul Sandoz]

Strengthen the specification of quoted captured values in relation to the operations captured values.

Consolidate duplicated code that computes captured values.

-------------

Commit messages:
 - Doc update
 - Doc update.
 - Refine spec of Quoted.capturedValues.
 - Remove JavaDoc on overridden methods
 - Remove trailing white space.
 - Refine support for captured values.

Changes: https://git.openjdk.org/babylon/pull/57/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=57&range=00
  Stats: 178 lines in 5 files changed: 87 ins; 77 del; 14 mod
  Patch: https://git.openjdk.org/babylon/pull/57.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/57/head:pull/57

PR: https://git.openjdk.org/babylon/pull/57