compiler/nir: Fix -Wunused-variable warnings in vars_tests.cpp
These only show up in debug builds, and were caught by our internal CI.
Signed-off-by: Matt Coster <matt.coster@imgtec.com>
These only show up in debug builds, and were caught by our internal CI.
Signed-off-by: Matt Coster <matt.coster@imgtec.com>