add remaining math methods (#524)

[mr-rodgers]

This Pull Request fixes/closes #524.

It changes the following (work-in-progress):

• Math.clz32()
• Math.expm1()
• Math.fround()
• Math.hypot()
• Math.log1p()
• Math.imul()

[codecov]

Codecov Report

Merging #525 into master will increase coverage by 0.35%.
The diff coverage is 94.20%.

@@            Coverage Diff             @@
##           master     #525      +/-   ##
==========================================
+ Coverage   68.10%   68.46%   +0.35%     
==========================================
  Files         169      169              
  Lines        9942    10080     +138     
==========================================
+ Hits         6771     6901     +130     
- Misses       3171     3179       +8     

Impacted Files	Coverage Δ
boa/src/builtins/math/mod.rs	75.89% <75.00%> (-0.18%)	⬇️
boa/src/builtins/math/tests.rs	100.00% <100.00%> (ø)

---

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 8b40e9e...e51ee81. Read the comment docs.

[HalidOdat]

Suggested change

	.and_then(|x| f64::from(x).to_u32())
	.map_or(32usize, |u| {
	let s = format!("{:032b}", u);
	s.chars().take_while(|x| *x == '0').count()
	})
	.and_then(|x| i32::from(x).leading_zeros())
	.unwrap_or(32)

A better way of doing this would we to use .leading_zeros() which would eliminate the allocation from format!

[pedropaulosuzuki]

Looks good to me. I'd write some more things on the tests, just to be sure. I know your implementation is correct, but maybe a new implementation in a future refactor might not be. Either way, looks pretty good to me.

[HalidOdat]

Looks perfect! The additional tests would be nice :)

[pedropaulosuzuki]

Looks good to me!!