glsl: handle ast_aggregate in has_sequence_subexpression. (v2)

glsl: handle ast_aggregate in has_sequence_subexpression. (v2)

GL43-CTS.compute_shader.work-group-size does
uniform uint g_uniform[gl_WorkGroupSize.z + 20] = { 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24 };

The initializer triggers the GLSL 4.30/GLES3 tests
for constant sequence subexpressions, so it doesn't
happen unless you are using those, so just return
false as this path is now reachable.

v2: update commit msg with diagnosis
Acked-by: Timothy Arceri <timothy.arceri@collabora.com>
Cc: "11.2 12.0" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>