Fix issues with output shapes.

This CL fixes two issues related to output shapes:

Dynamic output shape tests

- Before: Dynamic output shape tests have output dimensions all set to
          zero in the TestModel struct.
- After: The TestModel will always have fully-specified dimensions. The
         converter function createModel will assign zero dimensions to
	 output operands according to a flag testDynamicOutputShape.

Zero-sized outputs

- Before: Zero-sized outputs are assigned dummy values in test generator
          to generate a non-zero buffer.
- After: Zero-sized outputs have empty buffer in test generator and
         TestModel struct. The converter function createRequest will
	 allocate non-zero buffer.

Bug: 120601396
Test: NNT_static
Test: All VTS
Test: CTS
Change-Id: I8503ed4c439e9c490aef105ac01a662b4d6430d8
Merged-In: I8503ed4c439e9c490aef105ac01a662b4d6430d8
(cherry picked from commit 890040b982e4cae2362abffe439f8a39dfe08240)
31 files changed