Reduce UsageStats logspam.

When there are parsing errors while deobfuscating usage stats, it can
produce a lot of error logs. Condense and reduce the logging to a
minimal amount.

Also, keep track of the recently removed package tokens and dump them
to help debug these parsing errors.

Bug: 177610601
Test: adb shell dumpsys usagestats mappings 0
Change-Id: I860ee4b24d2ff2df88e536edca81920256257198