Currently the CPU stats are only updated once every mark termination,
but for writing robust tests, it's often useful to force this update.
Refactor the CPU stats accumulation out of gcMarkTermination and into
its own function. This is also a step toward real-time CPU stats.
While we're here, fix some incorrect documentation about dedicated GC
CPU time.
For #59749.
For #60276.
Change-Id: I8c1a9aca45fcce6ce7999702ae4e082853a69711
Reviewed-on: https://go-review.googlesource.com/c/go/+/487215
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>