[infra] Add iOS 13.4

Change-Id: I21ab46d77e8ebcc3b6a57cf2ed73f236cd103c5a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/292260
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
5 files changed