For the PS4 platform, we want to exclude certain headers from being included because we do not support the features they provide. To achieve this, we do not include any header files by default, and rely on the cpu target features to selectively enable supported header files. Compilers targeting the PS4 define SCE and individual features will be set automatically by the compiler's -target-cpu option (btver2 for the PS4).
The test change is needed because with this change, the test was failing because our SCE define was excluding everything, and there is no corresponding -target-cpu specified by the test to turn individual features back on. When no -target-cpu is selected, a generic cpu is assumed by the compiler with no additional feature support enabled. The fix I am adding is explicitly running each command with both 32/64bit generic triples.
I'm not sure why we need a version with and without -flax-vector-conversions=none. "none" is the strictest setting I think. So if we pass with that why do we need to check without it?