logd: mLastWorstPidOFSystem crash

(cherry pick from commit fa07f9dc)

mLastWorstPidOfSystem is filled with iterator references
that are not from AID_SYSTEM to aid the performance. But
we only clear entries from the list during erase if they
are from AID_SYSTEM. Remove the filter check in erase so
the stale references will be removed.

The conditions that caused this failure are difficult to
reproduce and are rare.

Test: gTests logd-unit-tests, liblog-unit-tests and logcat-unit-tests
Bug: 32247044
Bug: 31237377
Change-Id: Ie405dd643203b816cac15eef5c97600551cee450