Move fs-verity setup to post-commit

When fs-verity is being enabled, it currently drops the file/APK's page
cache and can cause performance issue. Move the work to post-commit
where the slower tasks are done. It's done before ART components because
in the future we'd like to add the APK's fs-verity digest to the
odex/vdex's header.

Bug: 259179666
Test: atest CtsAppSecurityHostTestCases:android.appsecurity.cts.ApkVerityInstallTest
Test: atest ApkVerityTest
Test: atest ChecksumsTest
Change-Id: I49f58b4976978bb5310f3589fff37d6bf0858a0f