liblog: android_log_isloggable failing apct

(cherry pick from commit efe8ecc1)

- periodic failures in apct, dropped second serial test
  in refresh_cache, trusting check_cache or global.
- The retry loop to see if is_loggable recovers of 1000
  was hiding subsequent tests, drop to 10 retries.
- On the whole, the average performance remains the same.

Bug: 25792367
Change-Id: I4110440ef46671d7a1c128689bde623808bed04f