These capabalities were added on declaration of the members, but
that is considered too aggressive, as those members are automatically
declared in some shaders that don't use them. Now, actual access
is needed to make the capabalities be declared.
This fixes some vulkanCTS tests that use struct arrays as a member of in/out interface blocks.
From Vulkan spec:
"If it is a not a Block, then the structure type must have a Location decoration. Its members are assigned consecutive locations in their declaration order, with the first member assigned to the location specified for the structure type. >>>>> The members, and their nested types, must not themselves have Location decorations <<<<"
From SPIR-V spec:
"When applied to structure-type members, the Decorations Noperspective, Flat, Patch, Centroid, and Sample can only be applied to the top-level members of the structure type. (Nested objects' types cannot be structures whose members are decorated with these decorations.)"
Before, it was only including explicit interface, sufficient for IO-Block-declared
oriented interface, but not sufficient for all modes GLSL might be used with
SPIR-V.
Two things are accomplished now:
1) each id will appear exactly once
2) the OpEntryPoint list will union static use with declarations
Structured control-flow rules allow leaving the middle of a construct through
a return, but not through a jump to a block that does a return.
Addresses issue #58.
