Add analysis benchmarks

[sbillig]

Three simple benchmarks so far:

• analyze library/core (which is quite small right now; this will be more useful as the core lib grows)
• parse all fe files in uitest/fixtures/
• parse and analyze all fe files in uitest/fixtures

cd crates/bench
cargo bench

analysis/analyze corelib
                        time:   [1.2870 ms 1.2906 ms 1.2946 ms]
                        change: [-0.3730% +0.0087% +0.4142%] (p = 0.97 > 0.05)
                        No change in performance detected.
Found 10 outliers among 100 measurements (10.00%)
  8 (8.00%) high mild
  2 (2.00%) high severe
analysis/uitest parsing time:   [1.6903 ms 1.6949 ms 1.6996 ms]
                        change: [-0.2576% +0.0639% +0.3805%] (p = 0.71 > 0.05)
                        No change in performance detected.
analysis/uitest diagnostics
                        time:   [28.317 ms 28.406 ms 28.502 ms]
                        change: [-0.5731% -0.0404% +0.4849%] (p = 0.88 > 0.05)
                        No change in performance detected.
Found 4 outliers among 100 measurements (4.00%)
  3 (3.00%) high mild
  1 (1.00%) high severe