glsl: link error if unsized array not-last in ssbo

glsl: link error if unsized array not-last in ssbo

If an unsized declared array is not the last in an SSBO
and an implicit size can not be defined on linking time,
the linker should raise an error instead of reaching
an assertion on GL.

This reverts part of commit 3da08e166415a745139c1127040a24e8a45dc553
getting back to the behavior of commit 5b2675093e863a52b610f112884ae12d42513770

The original patch was correct for GLES that should produce
a compile-time error but the linker error is still necessary
in desktop GL.

Fixes the following piglit tests:
tests/spec/arb_shader_storage_buffer_object/non_integral_size_array_member.shader_test
tests/spec/arb_shader_storage_buffer_object/unsized_array_member.shader_test

Reviewed-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Signed-off-by: Jose Maria Casanova Crespo <jmcasanova@igalia.com>