8350285: Shenandoah: Regression caused by ShenandoahLock under extreme contention

[dtmhuang]

Backport for ShenandoahLock performance regression issue. The fix involves sleeping for a very short duration every 3 yields, with the number of yields picked through manual testing.

Clean backport, ran GHA sanity checks and locally tested tier1, tier2, and hotspot_gc_shenandoah. test/jdk/java/nio/channels/FileChannel/directio/DirectIOTest.java sometimes fails locally, but it also sometimes failed before the fix.

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Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8350285 needs maintainer approval

Error

 ⚠️ OCA signatory status must be verified

Issue

• JDK-8350285: Shenandoah: Regression caused by ShenandoahLock under extreme contention (Bug - P4)

Reviewing

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Update a local copy of the PR:
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https://git.openjdk.org/jdk17u-dev/pull/3614.diff

[bridgekeeper]

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[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[dtmhuang]

/covered

[bridgekeeper]

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[shipilev]

Just to make sure, @robilad: @dtmhuang is from Amazon :)