HLSL output needs uniform information generated by the collectVariables()
step to be able to write uniform registers.

Tested manually by compiling a shader with a uniform with
shader_translator.

BUG=angleproject:1132

Change-Id: I91d19b5fa789b7b33cf76a654ffbbd17d279db01
Reviewed-on: https://chromium-review.googlesource.com/294962Tested-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>