cmd/go/internal/modfetch: more logging in TestConvertLegacyConfig

Make the test report git commands run when invoked with -v
(by setting the build -x flag).

Change-Id: I83a532a491eba3b5e330d37897d563e394950641
Reviewed-on: https://go-review.googlesource.com/117937
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
diff --git a/vendor/cmd/go/internal/modfetch/convert_test.go b/vendor/cmd/go/internal/modfetch/convert_test.go
index 509f5c6..1901b46 100644
--- a/vendor/cmd/go/internal/modfetch/convert_test.go
+++ b/vendor/cmd/go/internal/modfetch/convert_test.go
@@ -9,6 +9,7 @@
 	"strings"
 	"testing"
 
+	"cmd/go/internal/cfg"
 	"cmd/go/internal/modconv"
 	"cmd/go/internal/modfile"
 	"cmd/go/internal/webtest"
@@ -19,6 +20,14 @@
 	webtest.Hook()
 	defer webtest.Unhook()
 
+	if testing.Verbose() {
+		old := cfg.BuildX
+		defer func() {
+			cfg.BuildX = old
+		}()
+		cfg.BuildX = true
+	}
+
 	var tests = []struct {
 		path  string
 		vers  string