New API: DumpableContainer.removeDumpable.

Test: m update-api
Test: atest com.android.internal.util.DumpableContainerImplTest

Bug: 149254050
Bug: 217567642
CTS-Coverage-Bug: 149254050

Change-Id: I4efe99a545bd3db2308d0956eaa85e0f799f0f1d
5 files changed