MIDI CTS: remove tests that pass null callback

We switched from using a HashMap to a ConcurrentHashMap in the MidiManager.
The ConcurrentHashMap does not tolerate null keys.
Passing a null key is not a required part of the API.
So rather than modify the framework code, we just removed the tests
that passed a null key.

Bug: 23033283
Change-Id: I3ed96d9ce3f42187efd9b1f4d2f624e37acd71cd
Signed-off-by: Phil Burk <philburk@google.com>
1 file changed