Conformance test for glsl array of structs with first pos int or bool.

At the time of writing, in Mac OS X with some NVIDIA cards, reading an array of
structs using a loop variable where the struct has an int or bool as its first
member returns corrupted data.

This adds a test with three examples:
- struct with unused int in first position
- struct with unused bool in first position
- struct with used bool in first position
Merge pull request #534 from jenanwise/array-of-struct-with-int-first-position

Conformance test for glsl array of structs with first pos int or bool.