InOutImportExport: Process input calls first.
InOutImportExport: Process input calls first.

We cache some values to export during the visit process. If we visit
output calls first, and cache the argument value, but the value was
later invalidated by lowering input calls. The IR will be a mess.
So we need to make sure visit input calls first.

googlestadia/llpc,GPUOpen-Drivers/llpc,googlestadia/llpc,GPUOpen-Drivers/llpc,GPUOpen-Drivers/llpc,googlestadia/llpc,GPUOpen-Drivers/llpc,googlestadia/llpc,googlestadia/llpc,GPUOpen-Drivers/llpc