Benchmark tests

[InnocentZero]

This allows us to run the same benchmark test in an extended format, effectively allowing us to run the compiler passes over the benchmark many times without having to create extremely large files like in #49. Supersedes #49.

cc: @WindSoilder @ysthakur @kubouch

Sorry, this took more than a year 😅

[InnocentZero]

I'm having the following error in parse_def_iter10 (when parse_def is done on a file 10x the size). Not sure what's causing this, but it's probably my changes. I can't find where though. Would like some help to debug this.

thread 'main' panicked at src/compiler.rs:247:14:
internal error: missing source of span
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

thread 'main' panicked at library/core/src/panicking.rs:225:5:
panic in a function that cannot unwind
stack backtrace:
   0:     0x55954d591292 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::hdcfcb6d4c8489523
   1:     0x55954d5b97e3 - core::fmt::write::h8a494366950f23bb
   2:     0x55954d58dcf3 - std::io::Write::write_fmt::h6556609fca33d0b1
   3:     0x55954d5910e2 - std::sys::backtrace::BacktraceLock::print::hb2a626a81e06b2dc
   4:     0x55954d592513 - std::panicking::default_hook::{{closure}}::h4f78485264f12d10
   5:     0x55954d5922f5 - std::panicking::default_hook::h2c66fc99e962531d
   6:     0x55954d592f25 - std::panicking::rust_panic_with_hook::h33ac55f64bbd807d
   7:     0x55954d592c86 - std::panicking::begin_panic_handler::{{closure}}::h30e7cb89678a57fe
   8:     0x55954d591799 - std::sys::backtrace::__rust_end_short_backtrace::hed60f27456c16ced
   9:     0x55954d59294d - __rustc[de2ca18b4c54d5b8]::rust_begin_unwind
  10:     0x55954d5b7c4d - core::panicking::panic_nounwind_fmt::h6c46f1098922b4b6
  11:     0x55954d5b7ce2 - core::panicking::panic_nounwind::he501508d405a4565
  12:     0x55954d5b7da5 - core::panicking::panic_cannot_unwind::h864cccdfd8b0af98
  13:     0x55954d09fe3f - <tango_bench::dylib::ffi::SelfVTable as tango_bench::dylib::ffi::VTable>::estimate_iterations::h09be7c7a88ba4f98
  14:     0x55954d0bd89b - tango_bench::cli::solo_test::run_test::h446987ec59846956
  15:     0x55954d08f2b0 - tango_bench::cli::run::h62bc0419ef32c55f
  16:     0x55954d06eca8 - benchmarks::main::h8e34acc58bb0f660
  17:     0x55954d08b0b6 - std::sys::backtrace::__rust_begin_short_backtrace::hd55dee0726b6ff9f
  18:     0x55954d086312 - std::rt::lang_start::{{closure}}::hd516835e9f1b5166
  19:     0x55954d585e50 - std::rt::lang_start_internal::h34f9328d113fd60a
  20:     0x55954d06ece5 - main
  21:     0x7fecfdf22635 - <unknown>
  22:     0x7fecfdf226e9 - __libc_start_main
  23:     0x55954d065915 - _start
  24:                0x0 - <unknown>
thread caused non-unwinding panic. aborting.

EDIT: Seems to be an error because of my changes.

[InnocentZero]

Should be good to go now.