Disable FullStackTest.LargeRoomVP8_*thumb on iOS
Disable FullStackTest.LargeRoomVP8_*thumb on iOS

It fails for the same reason as on Android

BUG=webrtc:7301

Review-Url: https://codereview.webrtc.org/3017473002
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#19857}

TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc