RFR: JDK-8323684: TypeMirror.{getAnnotationsByType, getAnnotation} return uninformative results

[Joe Darcy]

Initial implementation to make TypeMirror.{getAnnotationsByType, getAnnotation} functional; tests to follow.

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Commit messages:
 - Appease jcheck.
 - Add regression tests.
 - JDK-8323684: TypeMirror.{getAnnotationsByType, getAnnotation} return uninformative results

Changes: https://git.openjdk.org/jdk/pull/17410/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17410&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8323684
  Stats: 155 lines in 4 files changed: 129 ins; 18 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/17410.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17410/head:pull/17410

PR: https://git.openjdk.org/jdk/pull/17410