Revert "perf: Simplify and fix __perf_install_in_context()"

This reverts commit b222498c9aa997db4e32daecab091720a1b08fd1.
Revert "perf: Remove task_ctx_sched_in()"

This reverts commit 1dca585f5544fb582c4bc595eea05672ff2b25c3.
Revert "perf: Clean up 'ctx' reference counting"

This reverts commit d33ab86be1ee0c4b77e0d253e070dceae08b9627.