Vulkan: Don't let glslang link shaders
Vulkan: Don't let glslang link shaders

The translator outputs intermediate shaders for Vulkan that are later to
be modified by the SPIR-V transformer.  glslang has no business trying
to link them.

Bug: angleproject:5740
Change-Id: I9ae418f54b91312b5fd0ef794acbc46a40261a0e
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2753096
Commit-Queue: Shahbaz Youssefi <582eeec4f08a2ccd61e3ef52115e6e7c571582de@chromium.org>
Reviewed-by: Ian Elliott <ac50c12f27752fd82643b0b72adab33538bb2c97@google.com>
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle