Not looking for other users right now, this is just enough to test
unzip/zip/zipinfo.
This includes tests for unzip and ziptool, along with a change to
unzip's behavior to fix AOSP `make dist` when using ziptool unzip.
Also add the boilerplate to run these tests on the device, in presubmit.
Fix command name in --help output.
Test: atest ziptool-tests
Change-Id: I5c0215a3ab8cb2cd5fc517ed9c188f81a7bf4520
Elliott Hughes