runtime: remove defer test log spam

runtime: remove defer test log spam

This appears to be leftover debugging
from CL 356011.

Change-Id: Ieeda0b7e297e0cb943827b28644135e6cad12e3c
Reviewed-on: https://go-review.googlesource.com/c/go/+/364555
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Trust: Dan Scales <danscales@google.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Dan Scales <danscales@google.com>
TryBot-Result: Go Bot <gobot@golang.org>