RFR: 8368093: Remove Stream::createPseudoHeaders

[Daniel Fuchs]

On Mon, 1 Dec 2025 17:45:53 GMT, Daniel Jeliński <djelinski at openjdk.org> wrote:

> The method was copied to Utils, and all uses were updated. Remove the method now.
> 
> The methods are still [identical](https://github.com/openjdk/jdk/blob/6cb1c8f9cfcb797af788ca8fb490f388cc68f525/src/java.net.http/share/classes/jdk/internal/net/http/common/Utils.java#L1326-L1354). Tests continue to pass.

Marked as reviewed by dfuchs (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/28583#pullrequestreview-3526724716