WPT test for html/canvas/element/pixel-manipulation/2d.imageData.create2.zero.html fails

FAIL message: assert_throws_dom: function "function() { ctx.createImageData(0.99, 10); }" did not throw

Cross-browser tests (as of bug report):

The test can be checked easily at:
https://wpt.fyi/results/html/canvas/element/pixel-manipulation/2d.imageData.create2.zero.html?label=experimental&label=master&aligned

Shifted the zero-check after width and height are clamped to int32s. Fixes the
use case where width and height are floats > 0 but < 1. These values are
clamped to 0, but no error is thrown, as opposed to the desired behavior.
Changed corresponding test to reflect that it is expected to PASS.

Backed out for causing damp failures.

Backout link: https://hg.mozilla.org/integration/autoland/rev/1098ab162ad2352f7623193c1bbb80834d0b5d3a

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&selectedTaskRun=C4_y9653TPGBxLLiuAPwEg.0&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=636bed8f02dc5b95dd1c3572c09fa4bf9bb92aed&searchStr=linux%2Cx64%2Cwebrender%2Cshippable%2Copt%2Ctalos%2Cperformance%2Ctests%2Ctest-linux64-shippable-qr%2Fopt-talos-damp-e10s%2Cdamp

Failure log: https://treeherder.mozilla.org/logviewer?job_id=325674078&repo=autoland

This fixes the DAMP failures and effectively preserves behavior.

(In reply to Atila Butkovits from comment #5)

Failure log: https://treeherder.mozilla.org/logviewer?job_id=325674078&repo=autoland

Code snippet:

[task 2021-01-02T22:56:17.593Z] 22:56:17 ERROR - PID 3956 | Handler function threw an exception: TypeError: can't access property "first", timings.REQUEST_HEADER is undefined
[task 2021-01-02T22:56:17.593Z] 22:56:17 INFO - PID 3956 | Stack: _getBlockedTiming@resource://devtools/server/actors/network-monitor/network-observer.js:1226:7
[task 2021-01-02T22:56:17.593Z] 22:56:17 INFO - PID 3956 | _setupHarTimings@resource://devtools/server/actors/network-monitor/network-observer.js:1419:31
[task 2021-01-02T22:56:17.593Z] 22:56:17 INFO - PID 3956 | _onTransactionClose@resource://devtools/server/actors/network-monitor/network-observer.js:1210:27
[task 2021-01-02T22:56:17.593Z] 22:56:17 INFO - PID 3956 | _dispatchActivity@resource://devtools/server/actors/network-monitor/network-observer.js:632:14
[task 2021-01-02T22:56:17.593Z] 22:56:17 INFO - PID 3956 | NetworkObserver.prototype.observeActivity<@resource://devtools/server/actors/network-monitor/network-observer.js:738:12
[task 2021-01-02T22:56:17.593Z] 22:56:17 INFO - PID 3956 | exports.makeInfallible/<@resource://devtools/shared/ThreadSafeDevToolsUtils.js:103:22
[task 2021-01-02T22:56:17.593Z] 22:56:17 INFO - PID 3956 | Line: 1226, column: 7
[task 2021-01-02T22:56:17.593Z] 22:56:17 INFO - PID 3956 | console.error: (new TypeError("can't access property "first", timings.REQUEST_HEADER is undefined", "resource://devtools/server/actors/network-monitor/network-observer.js", 1226))

https://hg.mozilla.org/mozilla-central/rev/442421e347a1
https://hg.mozilla.org/mozilla-central/rev/9f813973b02b