perfdata: fix go113 to use net/http directly

google.golang.org/appengine/urlfetch is no longer available post-go111.

Change-Id: Id810b9abf8c5f366bd642cecff3d33d077d2682b
Reviewed-on: https://go-review.googlesource.com/c/perf/+/220904
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

storage/appengine/app.go

diff --git a/storage/appengine/app.go b/storage/appengine/app.go
index 31042eb..d54302a 100644
--- a/storage/appengine/app.go
+++ b/storage/appengine/app.go
@@ -22,7 +22,6 @@
 	oauth2 "google.golang.org/api/oauth2/v2"
 	"google.golang.org/appengine"
 	aelog "google.golang.org/appengine/log"
-	"google.golang.org/appengine/urlfetch"
 	"google.golang.org/appengine/user"
 )
 
@@ -96,8 +95,7 @@
 	}
 	tok = tok[len("Bearer "):]
 
-	hc := urlfetch.Client(ctx)
-	service, err := oauth2.New(hc)
+	service, err := oauth2.New(http.DefaultClient)
 	if err != nil {
 		return "", err
 	}