tests: Move pure_eval under toxgen #4128

Job	Run time
Tasks (latest) (3.12, ubuntu-22.04)	2m 31s
Tasks (latest) (3.7, ubuntu-22.04)	2m 25s
Tasks (latest) (3.11, ubuntu-22.04)	2m 13s
Tasks (pinned) (3.8, ubuntu-22.04)	5m 9s
Tasks (latest) (3.10, ubuntu-22.04)	2m 25s
Tasks (pinned) (3.7, ubuntu-22.04)	5m 11s
Tasks (pinned) (3.13, ubuntu-22.04)	8m 43s
Tasks (pinned) (3.6, ubuntu-22.04)	4m 33s
Tasks (latest) (3.13, ubuntu-22.04)	3m 13s
Tasks (pinned) (3.10, ubuntu-22.04)	4m 56s
Tasks (pinned) (3.12, ubuntu-22.04)	6m 53s
Tasks (pinned) (3.11, ubuntu-22.04)	5m 31s
Tasks (pinned) (3.9, ubuntu-22.04)	4m 52s
All pinned Tasks tests passed	3s
	58m 38s

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