Revert "runtime/pprof: speed up CPU profiling shutdown"
Revert "runtime/pprof: speed up CPU profiling shutdown"

This reverts commit 1f0738c1577a55a6b7229b821ddfe762b84771d0.

Reason for revert: This May have caused issue 38567.

Change-Id: I2afa6a9d42cb29cfad09e706fb465c57e3774abd
Reviewed-on: https://go-review.googlesource.com/c/go/+/229301
Reviewed-by: Hyang-Ah Hana Kim <d7e82c3c07f92613bcbf9a1e88f6b96c13caa3b0@gmail.com>

golang/go,golang/go,cloudflare/go,CAFxX/go,nawawi/go,CAFxX/go,golang/go,akutz/go,akutz/go,CAFxX/go,CAFxX/go,cloudflare/go,golang/go,CAFxX/go,nawawi/go,cloudflare/go,nawawi/go,cloudflare/go,nawawi/go,CAFxX/go,akutz/go,golang/go,nawawi/go,CAFxX/go,golang/go,golang/go,nawawi/go,cloudflare/go,cloudflare/go,cloudflare/go,akutz/go,golang/go,akutz/go,nawawi/go,akutz/go,CAFxX/go,cloudflare/go,akutz/go,akutz/go,nawawi/go