Test run Parallelism of 1 should not result in deadlock

[dsa0x]

Fixes #

When #36323 introduced the parallelism flag for limiting plan/apply operations concurrency, we agreed that a new flag would likely be needed for the run parallelism. Until now, the value for run concurrency was not set and we have just been using the default of 10. That's why it never got surfaced that there is a bug where a deadlock would occur when the run parallelism is set to 1

What led me to this is discovering that a parallelism of 1 will result in a deadlock if nodes that create subgraphs also acquire the lock.

1.13.x

Rollback Plan

• If a change needs to be reverted, we will roll out an update to the code within 7 days.

Changes to Security Controls

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CHANGELOG entry

• This change is user-facing and I added a changelog entry.
• This change is not user-facing.

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