The correct type needs to be set so that HLSL output will be able to
disambiguate user-defined function calls correctly based on argument
types. HLSL output support will be added to precision emulation in a
future patch, which will also have tests that verify this patch.

The lack of correct type on the nodes is not known to cause any bugs
in GLSL output.

BUG=angleproject:1437

Change-Id: I53200df066ece0ab4bd7d7a6aab699d6a1ecb659
Reviewed-on: https://chromium-review.googlesource.com/358470Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>