Defaulting total to 1 for each function, adds up to the
counting error. testing/cover.go already does this once.

Fixes #20515

Change-Id: I0e3f524c2ccb628eb9a8f0a1f81c22365c24cf9a
Reviewed-on: https://go-review.googlesource.com/44337
Run-TryBot: Dhananjay Nakrani <dhananjayn@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>