Fix testConfigTtl CTS case

It would failed seldomly if TTL been triggered after getting
statsd stats. We have to sleep and wait short time to make sure
TTL has been triggered.

This is a cherrypick of aosp/1132136 and aosp/1143484 into rvc-dev.

Bug: 159415965
Test: run cts -m CtsStatsdHostTestCases -t
android.cts.statsd.metadata.MetadataTests#testConfigTtl
Merged-In: I8d5e0e1fb801635bd14b86c0e8a2c48b8d53f5c1
Change-Id: I3ef568d88cc172a62373ffa7527635f2ab9d42af