RFR: 8303431: [JVMCI] libgraal annotation API [v8]

[Doug Simon]

> This PR extends JVMCI with new API (`jdk.vm.ci.meta.Annotated`) for accessing annotations. The main differences from `java.lang.reflect.AnnotatedElement` are:
> * All methods in the `Annotated` interface explicitly specify requested annotation type(s). That is, there is no equivalent of `AnnotatedElement.getAnnotations()`.
> * Annotation data is returned in a map-like object (of type `jdk.vm.ci.meta.AnnotationData`) instead of in an `Annotation` object. This works better for libgraal as it avoids the need for annotation types to be loaded and included in libgraal.
>  
> To demonstrate the new API, here's an example in terms `java.lang.reflect.AnnotatedElement` (which `ResolvedJavaType` implements):
> 
>     ResolvedJavaMethod method = ...;
>     ExplodeLoop a = method.getAnnotation(ExplodeLoop.class);
>     return switch (a.kind()) {
>         case FULL_UNROLL -> LoopExplosionKind.FULL_UNROLL;
>         case FULL_UNROLL_UNTIL_RETURN -> LoopExplosionKind.FULL_UNROLL_UNTIL_RETURN;
>         ...
>     }
> 
> 
> The same code using the new API:
> 
> 
>     ResolvedJavaMethod method = ...;
>     ResolvedJavaType explodeLoopType = ...;
>     AnnotationData a = method.getAnnotationDataFor(explodeLoopType);
>     return switch (a.getEnum("kind").getName()) {
>         case "FULL_UNROLL" -> LoopExplosionKind.FULL_UNROLL;
>         case "FULL_UNROLL_UNTIL_RETURN" -> LoopExplosionKind.FULL_UNROLL_UNTIL_RETURN;
>         ...
>     }
> 
> 
> The implementation relies on new methods in `jdk.internal.vm.VMSupport` for parsing annotations and serializing/deserializing to/from a byte array. This allows the annotation data to be passed from the HotSpot heap to the libgraal heap.

Doug Simon has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 12 commits:

 - rephrased javadoc Annotated to more precisely describe which annotations are returned
 - fixed comment
 - Merge remote-tracking branch 'openjdk-jdk/master' into JDK-8303431
 - [skip ci] formatting fixes
 - addressed review feedback
 - Merge remote-tracking branch 'openjdk-jdk/master' into JDK-8303431
 - switched to use of lists and maps instead of arrays
 - fixed whitespace
 - added support for inherited annotations
 - Merge branch 'master' into JDK-8303431
 - ... and 2 more: https://git.openjdk.org/jdk/compare/525a91e3...362738a6

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Changes: https://git.openjdk.org/jdk/pull/12810/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12810&range=07
  Stats: 2319 lines in 34 files changed: 2268 ins; 23 del; 28 mod
  Patch: https://git.openjdk.org/jdk/pull/12810.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/12810/head:pull/12810

PR: https://git.openjdk.org/jdk/pull/12810