8376346: [lworld] Shenandoah support

[shipilev]

Noticed that Shenandoah tests are failing in current lworld. This should fix most of the issues ahead of mainline integration.

Additional testing:

• Linux x86_64 server fastdebug, hotspot_gc_shenandoah
• Linux x86_64 server fastdebug, hotspot_valhalla jdk_valhalla with -XX:+UseShenandoahGC

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Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• Change must be properly reviewed (1 review required, with at least 1 Committer)

Error

 ⚠️ Pull request body is missing required line: - [x] I confirm that I make this contribution in accordance with the [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai).

Issue

• JDK-8376346: [lworld] Shenandoah support (Enhancement - P4)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/valhalla.git pull/1971/head:pull/1971
$ git checkout pull/1971

Update a local copy of the PR:
$ git checkout pull/1971
$ git pull https://git.openjdk.org/valhalla.git pull/1971/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 1971

View PR using the GUI difftool:
$ git pr show -t 1971

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/valhalla/pull/1971.diff

[bridgekeeper]

👋 Welcome back shade! A progress list of the required criteria for merging this PR into lworld will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

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

[bridgekeeper]

@shipilev This pull request has been inactive for more than 8 weeks and will be automatically closed if another 8 weeks passes without any activity. To avoid this, simply issue a /touch or /keepalive command to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

[shipilev]

/touch

[openjdk]

@shipilev The pull request is being re-evaluated and the inactivity timeout has been reset.