8315774: Enable parallelism in vmTestbase/gc/g1/unloading tests

[cost0much]

Clean backport to make vmTestbase/gc/g1/unloading tests parallel. Passes GHA and vmTestbase/gc/g1/unloading tests.

time make run-test TEST="vmTestbase/gc/g1/unloading
Before:
1220.85s user 109.96s system 53% cpu 41:28.83 total
After:
1240.52s user 89.00s system 707% cpu 3:07.93 total

---

Progress

• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8315774 needs maintainer approval

Issue

• JDK-8315774: Enable parallelism in vmTestbase/gc/g1/unloading tests (Enhancement - P4 - Requested)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk11u-dev.git pull/3044/head:pull/3044
$ git checkout pull/3044

Update a local copy of the PR:
$ git checkout pull/3044
$ git pull https://git.openjdk.org/jdk11u-dev.git pull/3044/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 3044

View PR using the GUI difftool:
$ git pr show -t 3044

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk11u-dev/pull/3044.diff

Using Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back cost0much! A progress list of the required criteria for merging this PR into master 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.

[openjdk]

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

[openjdk]

⚠️ @cost0much This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[cost0much]

/approval request Makes vmTestbase/gc/g1/unloading tests parallel. Clean backport. Passes GHA and vmTestbase/gc/g1/unloading tests. Risk is low: test code only and no change to tests themself.

[openjdk]

@cost0much
8315774: The approval request has been created successfully.

[mlbridge]

Webrevs

• 00: Full (dd2d76cb)