net.urllib: cleanup parse_authority, add test

[ttytm]

Updates the internal urllib function parse_authority that is used by the public parse function. Adds tests.

As far as I could tell the current implementation was based of Go's implementation, which has a different error handling. With V it was possible to make the code more readable while managing to slightly improve the performance at the same time.

Performance test:

❯ v repeat -r 20 benchmarks/pa_gcc_new benchmarks/pa_gcc_old
Summary after 1 series x 20 runs (`>` is the first cmd)                                                                                                                            
 >  1       === `benchmarks/pa_gcc_new`
                232.0ms ± σ:   6.6ms, 224.8ms … 254.0ms
    2     +2.5% `benchmarks/pa_gcc_old`
                237.7ms ± σ:   4.3ms, 231.8ms … 251.2ms

❯ v repeat -r 20 benchmarks/pa_clang_new benchmarks/pa_clang_old
Summary after 1 series x 20 runs (`>` is the first cmd)                                                                                                                            
 >  1       === `benchmarks/pa_clang_new`
                206.1ms ± σ:   2.2ms, 202.2ms … 210.2ms
    2     +1.4% `benchmarks/pa_clang_old`
                209.0ms ± σ:   2.7ms, 204.9ms … 215.4ms

import net.urllib

fn main() {
	test_urls := [
		'https://joe:[email protected]:8080/som/url?param1=test1&param2=test2&foo=bar#testfragment',
		'ftp://[email protected]/',
		'http://j@ne:[email protected]',
		'http://jane:p@[email protected]/p@th?q=@go',
	]

	for _ in 0 .. 100_000 {
		for url in test_urls {
			urllib.parse(url)!
		}
	}
}

[spytheman]

Excellent work.