shader_checker: fix invalid iterator dereference (LunarXchange #60)
shader_checker: fix invalid iterator dereference (LunarXchange #60)

V2: Fix broken logic; fix another case of the same problem in
interface between shader stages.

Signed-off-by: Chris Forbes <5dcac483e7a6e31a5cbe89f38cc69dff8ee93dac@ijw.co.nz>

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools