internal/fetchdatasource: remove arbitrary test timeout

Kokoro tests are failing with this arbitrary timeout. Remove it.

Updates golang/go#59608

Change-Id: Ifd3d8cf02d5c14f54e505fa5812e8de7dbc6c5d5
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/484738
TryBot-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Robert Findley <rfindley@google.com>
diff --git a/internal/fetchdatasource/fetchdatasource_test.go b/internal/fetchdatasource/fetchdatasource_test.go
index ecc63fd..8f93105 100644
--- a/internal/fetchdatasource/fetchdatasource_test.go
+++ b/internal/fetchdatasource/fetchdatasource_test.go
@@ -12,7 +12,6 @@
 	"os"
 	"regexp"
 	"testing"
-	"time"
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/google/go-cmp/cmp/cmpopts"
@@ -117,7 +116,7 @@
 
 func setup(t *testing.T, testModules []*proxytest.Module, bypassLicenseCheck bool) (context.Context, *FetchDataSource, func()) {
 	t.Helper()
-	ctx, cancel := context.WithTimeout(context.Background(), 40*time.Second)
+	ctx, cancel := context.WithCancel(context.Background())
 
 	var client *proxy.Client
 	teardownProxy := func() {}