Add BigInt.asIntN() and BigInt.asUintN() functions

[Tropid]

This Pull Request fixes/closes #415.

It changes the following:

• Adds a BigInt.asUintN() function
• Adds a BigInt.asIntN() function
• Adds a to_index() function to the interpreter (https://tc39.es/ecma262/#sec-toindex)
• Adds a to_integer() function to the interpreter (https://tc39.es/ecma262/#sec-tointeger, this is probably related to ValueData::to_integer which seems to behave different than the function described in the standard, it also returns a 32 bit integer instead of a 64 bit integer)
• Adds a to_number() to the interpreter (https://tc39.es/ecma262/#sec-tonumber, this is also similar to value_to_rust_number which behaves a bit different)
• Also adds a few tests (mostly from test262) for to_index, to_integer, BigInt.asIntN, BigInt.asUintN

[codecov]

Codecov Report

Merging #468 into master will increase coverage by 0.68%.
The diff coverage is 96.52%.

@@            Coverage Diff             @@
##           master     #468      +/-   ##
==========================================
+ Coverage   66.39%   67.07%   +0.68%     
==========================================
  Files         146      147       +1     
  Lines        9350     9544     +194     
==========================================
+ Hits         6208     6402     +194     
  Misses       3142     3142              

Impacted Files	Coverage Δ
boa/src/exec/mod.rs	65.57% <81.81%> (+2.96%)	⬆️
boa/src/builtins/bigint/mod.rs	82.22% <100.00%> (+15.55%)	⬆️
boa/src/builtins/bigint/operations.rs	54.83% <100.00%> (+10.01%)	⬆️
boa/src/builtins/bigint/tests.rs	100.00% <100.00%> (ø)
boa/src/exec/tests.rs	100.00% <100.00%> (ø)
boa/src/exec/conditional/mod.rs	83.33% <0.00%> (-16.67%)	⬇️
boa/src/exec/field/mod.rs	73.33% <0.00%> (-8.49%)	⬇️
boa/src/builtins/value/conversions.rs	42.42% <0.00%> (-0.44%)	⬇️
boa/src/builtins/value/equality.rs	63.85% <0.00%> (-0.10%)	⬇️
... and 16 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a78934d...56045cc. Read the comment docs.

[HalidOdat]

This looks awesome! check my comments to see how we can improve it :)

[Razican]

I'm only missing a bit of documentation. Benchmarks failing was a small bug introduced in the benchmark compare action that should be fixed in the next rebuild.

[Razican]

This is good to go for me :)

[Tropid]

Thanks for the review and feedback. This is pretty much my first pull request on GitHub and I'm really amazed by the process.

Should I rebase the commits, so there are not as many small commits like "Remove extra comment in doc comment" and "Remove another extra comment in doc comment" (I did not see the "Add suggestion to batch" button at first)?

[Razican]

Thanks for the review and feedback. This is pretty much my first pull request on GitHub and I'm really amazed by the process.

You did great! Thanks for the contribution :)

Should I rebase the commits, so there are not as many small commits like "Remove extra comment in doc comment" and "Remove another extra comment in doc comment" (I did not see the "Add suggestion to batch" button at first)?

There is no need, we squash and merge all commits together when we merge :)

The only good thing about rebasing is that benchmarks will start showing here as comments. That's something we might change in the future, though (the fact that it requires for the PR to be rebased).

[HalidOdat]

This Looks perfect! Thanks for the contribution @Tropid