RFR: JDK-8305506: Add support for fractional values of SafepointTimeoutDelay [v3]

[Martin Doerr]

On Fri, 28 Apr 2023 13:46:57 GMT, Wojciech Kudla <duke at openjdk.org> wrote:

>> As stated in https://bugs.openjdk.org/browse/JDK-8305506 this change replaces SafepointTimeoutDelay as integer value with a floating point type to support sub-millisecond SafepointTimeout thresholds.
>> This is immensely useful for investigating time-to-safepoint issues in low latency space.
>
> Wojciech Kudla has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Removed dedicated format declaration for jdouble, added test case for floating point type of -XX:SafepointTimeoutDelay

LGTM. Thanks for the updates.

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Marked as reviewed by mdoerr (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13373#pullrequestreview-1408722371