Replace printing codegen args with tracing

[LegNeato]

Depends on #193.

This removes the following options and replaces them with tracing:

• --specializer-debug => RUSTGPU_LOG=rustc_codegen_spirv::specializer=debug
• --print-zombie => RUSTGPU_LOG=print_zombie=debug
• --print-all-zombie => RUSTGPU_LOG=print_all_zombie=debug

[LegNeato]

Questions:

1. Do we want some sort of prefix for all these instead of print for future expansion?
2. Do we want to do kebab case or underscore?

[Firestar99]

Suggestion: use the profiling crate instead of tracing

Profiling uses features to specify which profiler you want to use, and ofc it has profile-with-tracing to forward all the zones to tracing. But can also support other profilers, like the excellent tracy profiler. And only the final binary has to specify the features, the intermediary crates can just use profiling without any features and incur no runtime overhead or feature forwarding hell.
However, debugging via logging would no longer be universally available and require a feature flag to work.

[LegNeato]

I think that is a good idea, but this isn't for profiling--just logging debug data. Rustc uses tracing so I'd prefer to start with the same solution. Looks like profiling suggests still using tracing for non-profiling / more advanced use cases. We do want profiling, but that is orthogonal (and can use tracing as its backend)

[LegNeato]

I also found https://docs.rs/tracing-tracy/latest/tracing_tracy/. Not sure which way is ultimately better, will probably require some hands on experience.

[LegNeato]

Looks like rustc has profiling built in, so we should probably use that for profiling I think.