Fixed infinite loop in retry manager

Added a safer check to detect the case when all APNs
are permanently failed. The complexity changes from
O(N) to O(N^2). Most of the time N=1 and was never
greater than 3, so this should not affect the performance.

Fix: 157187054
Test: RetryManager unit tests
Change-Id: I74af173c5d10b4f4f7b26d8d931e9b920297f37e