build-exe: allow combination of -fno-emit-bin and --verbose-air
Currently, `zig build-exe -fno-emit-bin --verbose-air src/main.zig`
results in no output at all. With this refactor, it dumps AIR
and then exits without invoking LLVM, as expected
e02b9f458dbfredl committed on 9/7/2022, 11:53:31 AM· committed by Veikka Tuominenparente283a40