Fix header parser (#1808)

[ksw2000]

See issue #1808. When FastHTTP receives a header value suffixed or prefixed with tabs, they should be stripped.

[erikdubbelboer]

Can you also add a test that shows that gets the value and shows the tabs are stripped?

[ksw2000]

I have added tests for the parser of ResponseHeader and RequestHeader. Before making code changes, TestIssue1808 could not pass. Additionally, my ground truth is compared against the parsing results of Go's built-in net/http package, which means our parser handles tabs in the same way as Go's built-in parser.

When I made the pull request, there was one test that did not pass, but in my opinion, it is unrelated to the changes I made.

[erikdubbelboer]

Thanks!