os/exec: PATH in windows ErrNotFound is not escaped

[xhit]

What version of Go are you using (go version)?

$ go version
1.14.2

Does this issue reproduce with the latest release?

Yes.

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
set GO111MODULE=
set GOARCH=amd64
set GOBIN=
set GOCACHE=C:\Users\sdelacruz\AppData\Local\go-build
set GOENV=C:\Users\sdelacruz\AppData\Roaming\go\env
set GOEXE=.exe
set GOFLAGS=
set GOHOSTARCH=amd64
set GOHOSTOS=windows
set GOINSECURE=
set GONOPROXY=
set GONOSUMDB=
set GOOS=windows
set GOPATH=C:\Users\sdelacruz\Documents\go
set GOPRIVATE=
set GOPROXY=https://proxy.golang.org,direct
set GOROOT=C:\Users\sdelacruz\sdk\go1.14.2
set GOSUMDB=sum.golang.org
set GOTMPDIR=
set GOTOOLDIR=C:\Users\sdelacruz\sdk\go1.14.2\pkg\tool\windows_amd64
set GCCGO=gccgo
set AR=ar
set CC=gcc
set CXX=g++
set CGO_ENABLED=1
set GOMOD=C:\Users\sdelacruz\Documents\go\src\sdi\go.mod
set CGO_CFLAGS=-g -O2
set CGO_CPPFLAGS=
set CGO_CXXFLAGS=-g -O2
set CGO_FFLAGS=-g -O2
set CGO_LDFLAGS=-g -O2
set PKG_CONFIG=pkg-config
set GOGCCFLAGS=-m64 -mthreads -fmessage-length=0 -fdebug-prefix-map=C:\Users\SDELAC~1\AppData\Local\Temp\go-build038950518=/tmp/go-build -gno-record-gcc-switches 

What did you do?

package main

import (
	"log"
	"os/exec"
	
)

func main() {
	cmd := exec.Command("pin", "google.com")
	err := cmd.Start()
	if err != nil {
		log.Fatal(err)
	}
}

What did you expect to see?

exec: "pin": executable file not found in %PATH%

What did you see instead?

exec: "pin": executable file not found in %!P(MISSING)ATH%!(NOVERB)

[gopherbot]

Change https://golang.org/cl/233198 mentions this issue: os/exec: escape percent literal for Windows PATH

[xhit]

Ignore the issue. I used a custom log package by mistake.