RFR: JDK-8267936: PreserveAllAnnotations option doesn't expose the annotation to Java code

[Jaroslav Tulach]

This PR exposes runtime invisible annotations via `Class.getAnnotation` when `-XX:+PreserveAllAnnotations` option is passed to the JVM.

Existing `-XX:+PreserveAllAnnotations` option can be very useful for code that needs to access annotations with `RetentionPolicy.CLASS` without the need to parse the .class files manually. While the RuntimeInvisibleAnnotations are kept in the runtime, they are not visible via java.lang.reflect API. I assume that's just an omission.

This PR provides a test and a single line fix that makes `-XX:+PreserveAllAnnotations` useful in cooperation with `Class.getAnnotation(...)`.

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Commit messages:
 - Expose runtime invisible annotations via Class.getAnnotation when -XX:+PreserveAllAnnotations is on

Changes: https://git.openjdk.java.net/jdk/pull/4245/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4245&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267936
  Stats: 65 lines in 2 files changed: 61 ins; 2 del; 2 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4245.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4245/head:pull/4245

PR: https://git.openjdk.java.net/jdk/pull/4245