Auto merge of #27851 - ghostd:fix-nosniff, r=jdm

Fix some 'nosniff' tests

This PR implements some standard function to work with headers, hence it fixes some 'nosniff' test/

I create a PR as Draft because i have some questions:
* i added the code info the `net` module instead of `script::dom::headers` to avoid some cyclic dependencies... but i'm not sure about this choice. Is there another potential location to put this code?
* i used String object to match the spectification (it states to collect sequences of "code points", but some code use byte arrays. Should i change the code to work with bytes?

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tests/wpt/metadata/fetch/nosniff/parsing-nosniff.window.js.ini

@@ -8,6 +8,3 @@
   [X-Content-Type-Options%3A%20nosniff%0C]
     expected: FAIL
 
-  [X-Content-Type-Options%3A%20nosniff%2C%2C%40%23%24%23%25%25%26%5E%26%5E*()()11!]
-    expected: FAIL
-