Merge pull request #399 from Watson1978/fix-rmem-page-ownership #535

Job	Run time
head-versions (ubuntu, jruby-head)	59s
head-versions (ubuntu, ruby-head)	1m 13s
mri (ubuntu-latest, 3.2)	42s
valgrind	4m 59s
other (ubuntu, truffleruby)	2m 52s
mri (windows-latest, 3.2)	2m 25s
other (ubuntu, jruby-9.4)	54s
mri (ubuntu-latest, 3.5)	34s
mri (ubuntu-latest, 3.4)	42s
mri (ubuntu-latest, 4.0)	34s
mri (ubuntu-latest, 2.5)	39s
mri (ubuntu-latest, 2.7)	45s
mri (ubuntu-latest, 3.1)	37s
mri (macos-latest, 3.2)	42s
mri (ubuntu-latest, 2.6)	39s
mri (macos-latest, 2.6)	1m 5s
mri (ubuntu-latest, 3.3)	39s
mri (windows-latest, 2.5)	2m 33s
mri (ubuntu-latest, 3.0)	40s
	24m 13s

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