runtime: clean up profiling data files produced by TestCgoPprof

Fixes #15541

Change-Id: I9b6835157db0eb86de13591e785f971ffe754baa
Reviewed-on: https://go-review.googlesource.com/22783
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/runtime/crash_cgo_test.go

@@ -10,6 +10,7 @@ import (
 	"bytes"
 	"fmt"
 	"internal/testenv"
+	"os"
 	"os/exec"
 	"runtime"
 	"strings"
@@ -250,6 +251,7 @@ func TestCgoPprof(t *testing.T) {
 		t.Fatal(err)
 	}
 	fn := strings.TrimSpace(string(got))
+	defer os.Remove(fn)
 
 	top, err := exec.Command("go", "tool", "pprof", "-top", "-nodecount=1", exe, fn).CombinedOutput()
 	if err != nil {