fix: remove the unit test for NewFileCache error

Signed-off-by: Junjie Gao <junjiegao@microsoft.com>

Author: JeyJeyGao

cmd/notation/verify_test.go

@@ -19,7 +19,6 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
-	"runtime"
 	"testing"
 
 	"github.com/notaryproject/notation-go/dir"
@@ -119,18 +118,6 @@ func TestGetVerifier(t *testing.T) {
 			t.Fatalf("expected %s, but got %s", expectedErrMsg, err)
 		}
 	})
-
-	t.Run("failed to new crl file cache", func(t *testing.T) {
-		if runtime.GOOS == "windows" {
-			t.Skip("skipping test on Windows")
-		}
-		dir.UserCacheDir = "/cache"
-		expectedErrMsg := "failed to create crl file cache: mkdir /cache: permission denied"
-		_, err := getVerifier(context.Background())
-		if err == nil || err.Error() != expectedErrMsg {
-			t.Fatalf("expected %s, but got %s", expectedErrMsg, err)
-		}
-	})
 }
 
 func dummyOCIPolicyDocument() trustpolicy.OCIDocument {