Modify test generator to produce new test model struct.

Generate the test models in the original example files. Model files for
CTS and VTS are no longer needed.

Note that the generators will not produce correct tests for dynamic
output shape tests. This will be fixed in a later CL submitted together.

Bug: 120601396
Bug: 138718240
Test: NNT_static
Test: All VTS
Test: CTS
Change-Id: Ia4a4eb18a554bb7443fed3bd864543008a626396