[ Merge of http://go/wvgerrit/95406 ]
There was an issue with DeleteEntry() where it would result in an
invalid table state if shrinking the usage table when the number of
sessions is at its max.
This required changing how the usage table invalidates entries. Now,
after invalidating an entry (marking an entry as kStorageTypeUnknown)
the table is defragmented if specified to.
Defragmentation involves:
1) Move valid entries near the end of the table to the position of
invalid entries near the front of the table.
2) Shrinking the table to cut off trailing invalid entries.
This change updates the existing tests to pass, but still needs new
tests for some of the edge cases.
Bug: 150887808
Bug: 149100568
Test: Linux unit tests and Android unit tests
Change-Id: I70c7b296e5e4b367746fcdaabbf0f12dcfb39230
da48461ba2