RFR: 8307652: sealed class hierarchy graph doesn't distinguish non-sealed classes [v2]

[Per Minborg]

On Tue, 16 May 2023 17:16:57 GMT, Chen Liang <liach at openjdk.org> wrote:

>> `@sealedGraph` had a mechanism to render non-sealed classes differently, but it's useless because the graph nodes are not bordered. This patch converts the non-sealed classes to be rendered in italics instead.
>> 
>> An example of `ConstantDesc`, which has a sealed hierarchy except `DynamicConstantDesc`:
>> JDK 20:
>> ![image](https://user-images.githubusercontent.com/7806504/236991678-e30c181a-cb1f-407a-b3e0-f648fe2df788.png)
>> 
>> This patch:
>> ![image](https://github.com/openjdk/jdk/assets/7806504/4fb8ec10-4f10-4902-8b9d-107b3644b2cf)
>
> Chen Liang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:
> 
>  - Use an edge and node to indicate non-sealed hierarchy
>  - Merge branch 'master' into fix/sealedgraph-nonsealed
>  - 8307652: sealed class hierarchy graph doesn't distinguish non-sealed classes

These changes look very good. A significant improvement to the graph rendering.

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Marked as reviewed by pminborg (Committer).

PR Review: https://git.openjdk.org/jdk/pull/13877#pullrequestreview-1429913989