This patch adds geometry shader variants to the code-generated
built-in function tests produced by gen_builtin_uniform_tests.py and
gen_constant_array_size_tests.py.

Note that there are two ways in which an implementation may expose
geometry shader support: via GLSL 1.50 or via ARB_geometry_shader4.
After some discussion on IRC, I've provisionally decided to write most
of the geometry shader tests using ARB_geometry_shader4, and then only
supply GLSL-1.50-based tests for basic santy testing and to cover the
cases where GLSL 1.50 and ARB_geometry_shader4 differ.

Rationale: (a) Mesa is likely to implement ARB_geometry_shader4
support before GLSL 1.50 support (since Bryan Cain already has some
work-in-progress geometry shader patches that use
ARB_geometry_shader4).  (b) there are likely to be some
implementations that support geometry shaders but not GLSL 1.50
(e.g. Mesa softpipe, or i965 Gen5); writing most of the tests for
ARB_geometry_shader4 ensures that those implementations are
well-covered.

Accordingly, these code-generated tests are written entirely using
ARB_geometry_shader4.

Reviewed-by: Eric Anholt <eric@anholt.net>