Non-printable characters filtered by collection lead to MISSING results on wpt.fyi

Not sure this is the right repo for this, but...

https://wpt.fyi/results/FileAPI/blob/Blob-constructor.html?label=master&label=experimental contains two cases where platforms end up with different names for the same test, leading to confusing MISSING lines:

NOTE: The "function" case towards the top is because Safari introduces a space:

String(function() {}) === "function () {}"

... so the outputs from the different browsers don't match, leading to these "MISSING" lines. That seems like a straight up interop bug. Just mentioning it here since it could be distracting. That's not an issue for this repo.

The "image/gif;" case is more subtle and seems relevant. There's a non-printable U+007F code point at the end of the string in the test. In both Chrome and Safari, the DOM when the test is complete does contain the U+007F code point. But somehow by the time the results get to WPT.FYI the Chrome/Edge results retain the U+007F character but the Firefox/Safari results have dropped the code point, leading to a mismatch.

Since this seems to relate to the results collection pipeline rather than either the tests (WPT) or the correlation/display (WPT.FYI), filing the issue here.

No file or test entry point is identified; start by tracing the results collection pipeline described in the issue and compare handling of U+007F across browser results. Done means the character is preserved consistently and the differing results no longer produce misleading MISSING lines.