Disregard healing disks in crawling (#10349)

When crawling never use a disk we know is healing.

Most of the change involves keeping track of the original endpoint on xlStorage
and this also fixes DiskInfo.Endpoint never being populated.

Heal master will print `data-crawl: Disk "http://localhost:9001/data/mindev/data2/xl1" is 
Healing, skipping` once on a cycle (no more often than every 5m).

cmd/xl-storage_windows_test.go

@@ -48,7 +48,7 @@ func TestUNCPaths(t *testing.T) {
 
 	// Instantiate posix object to manage a disk
 	var fs StorageAPI
-	fs, err = newXLStorage(dir, "")
+	fs, err = newLocalXLStorage(dir)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -83,7 +83,7 @@ func TestUNCPathENOTDIR(t *testing.T) {
 	defer os.RemoveAll(dir)
 
 	var fs StorageAPI
-	fs, err = newXLStorage(dir, "")
+	fs, err = newLocalXLStorage(dir)
 	if err != nil {
 		t.Fatal(err)
 	}