Add tests to avoid inconsistent extension names

On v2.1/v3 API, extension names should be camelcases.
I0dc6c23ffcdcf97fc52d3575d521692805ffd9e3 has fixed inconsistent
names already.
This patch adds tests for blocking these inconsistent name/alias
additions in the future.

Change-Id: I3c9ee3f59fd17394b251fedf8df592e5d6304962
Related-Bug: #1315597
Merge "Add tests to avoid inconsistent extension names"