Benchmark clif release builds with ./y.rs bench

[bjorn3]

When enabling optimizations for cg_clif there is a non-trivial runtime perf improvement at a very small compile time cost. This is probably due to a combination of MIR inlining and Cranelift's e-graph based optimizations.

On AArch64 I'm getting a ~30% improvement over optimizations disabled for cg_clif:

``` Benchmark 1: ./raytracer_cg_llvm Time (mean ± σ): 7.049 s ± 0.022 s [User: 7.041 s, System: 0.008 s] Range (min … max): 7.021 s … 7.097 s 10 runs Benchmark 2: ./raytracer_cg_clif Time (mean ± σ): 4.923 s ± 0.006 s [User: 4.917 s, System: 0.006 s] Range (min … max): 4.913 s … 4.931 s 10 runs Benchmark 3: ./raytracer_cg_clif_opt Time (mean ± σ): 3.780 s ± 0.011 s [User: 3.775 s, System: 0.006 s] Range (min … max): 3.770 s … 3.810 s 10 runs Summary './raytracer_cg_clif_opt' ran 1.30 ± 0.00 times faster than './raytracer_cg_clif' 1.86 ± 0.01 times faster than './raytracer_cg_llvm' ```

at a small compile time cost that almost entirely vanishes due to the huge amount of available parallelism on the AArch64 machine:

``` Benchmark 1: RUSTC=rustc cargo build [...] Time (mean ± σ): 11.398 s ± 0.127 s [User: 37.814 s, System: 5.434 s] Range (min … max): 11.150 s … 11.579 s 10 runs Benchmark 2: RUSTC=rustc /home/gh-bjorn3/cg_clif/./dist/cargo-clif build [...] Time (mean ± σ): 9.758 s ± 0.124 s [User: 24.436 s, System: 5.305 s] Range (min … max): 9.588 s … 10.033 s 10 runs Benchmark 3: RUSTC=rustc /home/gh-bjorn3/cg_clif/./dist/cargo-clif build --release [...] Time (mean ± σ): 9.741 s ± 0.212 s [User: 26.540 s, System: 5.244 s] Range (min … max): 9.564 s … 10.314 s 10 runs Summary 'RUSTC=rustc /home/gh-bjorn3/cg_clif/./dist/cargo-clif build --release [...]' ran 1.00 ± 0.03 times faster than 'RUSTC=rustc /home/gh-bjorn3/cg_clif/./dist/cargo-clif build [...] 1.17 ± 0.03 times faster than 'RUSTC=rustc cargo build [...]' ```

On github actions (x86_64) which has much less available parallelism I get somewhat smaller but still really nice perf improvement of ~20%:

``` Benchmark 1: ./raytracer_cg_llvm Time (mean ± σ): 4.294 s ± 0.053 s [User: 4.287 s, System: 0.005 s] Range (min … max): 4.241 s … 4.382 s 10 runs Benchmark 2: ./raytracer_cg_clif Time (mean ± σ): 4.095 s ± 0.058 s [User: 4.089 s, System: 0.005 s] Range (min … max): 4.019 s … 4.199 s 10 runs Benchmark 3: ./raytracer_cg_clif_opt Time (mean ± σ): 3.385 s ± 0.083 s [User: 3.380 s, System: 0.003 s] Range (min … max): 3.323 s … 3.606 s 10 runs Summary './raytracer_cg_clif_opt' ran 1.21 ± 0.03 times faster than './raytracer_cg_clif' 1.27 ± 0.03 times faster than './raytracer_cg_llvm' ```

At the cost of ~6% slower compilation:

``` Benchmark 1: RUSTC=rustc cargo build [...] Time (mean ± σ): 14.992 s ± 0.143 s [User: 23.646 s, System: 3.589 s] Range (min … max): 14.815 s … 15.209 s 10 runs Benchmark 2: RUSTC=rustc /home/runner/work/rustc_codegen_cranelift/rustc_codegen_cranelift/./dist/cargo-clif build [...] Time (mean ± σ): 10.955 s ± 0.054 s [User: 16.081 s, System: 3.422 s] Range (min … max): 10.889 s … 11.044 s 10 runs Benchmark 3: RUSTC=rustc /home/runner/work/rustc_codegen_cranelift/rustc_codegen_cranelift/./dist/cargo-clif build --release [...] Time (mean ± σ): 11.632 s ± 0.117 s [User: 17.578 s, System: 3.311 s] Range (min … max): 11.468 s … 11.883 s 10 runs Summary 'RUSTC=rustc /home/runner/work/rustc_codegen_cranelift/rustc_codegen_cranelift/./dist/cargo-clif build [...]' ran [BENCH RUN] ebobby/simple-raytracer 1.06 ± 0.01 times faster than 'RUSTC=rustc /home/runner/work/rustc_codegen_cranelift/rustc_codegen_cranelift/./dist/cargo-clif build --release [...]' 1.37 ± 0.01 times faster than 'RUSTC=rustc cargo build [...]' ```

Be aware however that this is for a single benchmark which is not all that representative of real life performance. Make sure to benchmark yourself on your workload. I did love to hear what the results would be for you.