Sync WPT with upstream (08-10-2019)

[servo-wpt-sync]

Automated downstream sync of changes from upstream as of 08-10-2019.
[no-wpt-sync]
r? @servo-wpt-sync

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This change is 

[servo-wpt-sync]

@bors-servo r+

[bors-servo]

📌 Commit 4a65c0d has been approved by servo-wpt-sync

[highfive]

Heads up! This PR modifies the following files:

• @jgraham: tests/wpt/webgl/meta/conformance2/rendering/canvas-resizing-with-pbo-bound.html.ini

[highfive]

Warning

• These commits modify unsafe code. Please review it carefully!

[jdm]

@bors-servo try=wpt

[bors-servo]

⌛ Trying commit adaf292 with merge 9d0086f...

[bors-servo]

💔 Test failed - linux-rel-wpt

[jdm]

@bors-servo r+

[bors-servo]

📌 Commit 6764635 has been approved by jdm

[bors-servo]

⌛ Testing commit 6764635 with merge 8afd5da...

[bors-servo]

💔 Test failed - linux-rel-css

[jdm]

@bors-servo retry

• Intermittent panic in fetch test (/fetch/stale-while-revalidate/fetch.html) #24399

[bors-servo]

⌛ Testing commit 6764635 with merge 23413fe...

[bors-servo]

💔 Test failed - status-taskcluster

[CYBAI]

Interesting. These 2 tests are passed in mac build (5/6) now 🤔

{
    "status": "PASS", 
    "group": "default", 
    "message": null, 
    "stack": null, 
    "subtest": "Autofocus elements in top-level browsing context's documents with URI fragments should be skipped.", 
    "test": "/html/interaction/focus/the-autofocus-attribute/skip-document-with-fragment.html", 
    "line": 71369, 
    "action": "test_result", 
    "expected": "TIMEOUT"
}
{
    "status": "OK", 
    "group": "default", 
    "message": null, 
    "stack": null, 
    "subtest": null, 
    "test": "/html/interaction/focus/the-autofocus-attribute/skip-document-with-fragment.html", 
    "line": 71370, 
    "action": "test_result", 
    "expected": "TIMEOUT"
}

and another mac build (2/6) failure is #21067

[jdm]

#24407