Deflake AckNotifierWithPacketLossAndBlockedSocket
Deflake AckNotifierWithPacketLossAndBlockedSocket

This CL removes flakes in this test, but hasn't yet found the root cause of the extra 16 bytes.

Test-only

PiperOrigin-RevId: 311718153
Change-Id: I9f494b03089bc6f5c0b2f2566ca4071bba35c779

google/quiche,google/quiche,google/quiche,google/quiche