Add conformance tests for declaring empty arrays

We do not have coverage for declaring empty arrays. We should test both:

float f[];
float f[0];

We already have tests for negative size inside ogles/GL/build/array*

Start with the existing tests under ogles/GL/build/array*, which already cover negative array sizes. Add conformance tests for float f[] and float f[0], then run the relevant array test suite and confirm both declarations are covered.

Written by the indexing model from the issue text.