RFR: 8368817: Convert JDK_Version::to_string to use stringStream instead of jio_snprintf-chain

[Johan Sjölen]

On Tue, 30 Sep 2025 02:53:00 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please review this change to JDK_Version::to_string to use stringStream to
> accumulate the version string in the buffer, rather than using jio_snprintf to
> write the various pieces.
> 
> Testing: mach5 tier1
> Locally manually examined result of JDK_Version for builds configured with
> different values for various version parameters.

Marked as reviewed by jsjolen (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/27567#pullrequestreview-3283269736