RFR: 8258422: Cleanup unnecessary null comparison before instanceof check in java.base [v4]

[Aleksei Efimov]

On Wed, 16 Dec 2020 10:32:12 GMT, Andrey Turbanov <github.com+741251+turbanoff at openjdk.org> wrote:

>> 8258422: Cleanup unnecessary null comparison before instanceof check in java.base
>
> Andrey Turbanov has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8258422: Cleanup unnecessary null comparison before instanceof check in java.base
>   take advantage of "flow scoping" to eliminate casts

Thank you for checking `HttpURLConnection` and `Socket`.
The latest version looks good to me.

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Marked as reviewed by aefimov (Committer).

PR: https://git.openjdk.java.net/jdk/pull/20