Add benchmark for ELF "str2symtab" creation

[d-e-s-o]

Add a benchmark for the creation of our ELF "str2symtab". This creation should trigger a good chunk of our data structure traversing and "parsing" paths. The performance is roughly as follows:

  $ cargo bench --features=nightly -- bench_str2sym_creation
  > test elf::parser::tests::bench_str2sym_creation  ... bench:  26,023,493.50 ns/iter (+/- 644,362.62)

The main reason for the addition of the benchmark is to get an idea how much performance we lost due to recent ELF parser changes: both the introduction of 32 bit support as well as the logic for working with different backends is assumed to have some runtime impact. Backporting the benchmark on top of commit 4688aa0 ("cli: Rework tracing output") results in the following performance numbers before said ELF changes:

  $ cargo bench --features=nightly -- bench_str2sym_creation
  > test elf::parser::tests::bench_str2sym_creation  ... bench:  25,233,120.60 ns/iter (+/- 496,742.81)

The difference is reproducible, but arguably small and acceptable. We may be able to speed things up a bit more via the usage of smaller indexes.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.47%. Comparing base (3f4b694) to head (4b62532).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #943      +/-   ##
==========================================
- Coverage   94.58%   94.47%   -0.12%     
==========================================
  Files          57       57              
  Lines       10626    10644      +18     
==========================================
+ Hits        10051    10056       +5     
- Misses        575      588      +13     

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