RFR: 8344148: Add an explicit compiler phase for warning generation [v3]

[Vicente Romero]

On Thu, 2 Jan 2025 19:17:54 GMT, Archie Cobbs <acobbs at openjdk.org> wrote:

>> Please review this patch which does some minor refactoring to the compiler:
>> * Create a new `WARN` phase which can be a dedicated home for (new) lint/warning logic
>> * Create a new `WarningAnalyzer` singleton whose job is to invoke such lint/warning logic
>> * Move `ThisEscapeAnalyzer` out of `Flow` (where it doesn't belong) and into `WarningAnalyzer`
>> * Refactor `ThisEscapeAnalyzer` to be a context singleton like all other such classes
>> 
>> See [JDK-8344148](https://bugs.openjdk.org/browse/JDK-8344148) for details.
>
> Archie Cobbs 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 six additional commits since the last revision:
> 
>  - Bump copyright year to 2025.
>  - Merge branch 'master' into JDK-8344148
>  - Merge branch 'master' into JDK-8344148
>  - Merge branch 'master' into JDK-8344148
>  - Update copyright years.
>  - Add an explicit compiler phase for warning generation.

lgtm

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Marked as reviewed by vromero (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/22088#pullrequestreview-2532708559