make owner a private field of `PType` #27630

Job	Run time
ubuntu-20.04 (batch: allowed_failures)	5m 1s
ubuntu-20.04 (batch: 0_3)	28m 11s
ubuntu-20.04 (batch: 1_3)	26m 1s
ubuntu-20.04 (batch: 2_3)	21m 14s
macos-13 (batch: allowed_failures)	7m 38s
macos-13 (batch: 0_3)	42m 51s
macos-13 (batch: 1_3)	38m 10s
macos-13 (batch: 2_3)	28m 20s
	3h 17m 26s

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