Convert the test-suite to use the Fetch API rather than XMLHttpRequest

[Snuffleupagus]

• Convert the test-suite to use the Fetch API rather than XMLHttpRequest

  The Fetch API should be well supported across modern browsers, see https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API#browser_compatibility, and allows simplifying the code thanks to all of its method returning Promises.

  This patch also introduces template strings, rather than using manual string concatenation, in a few spots in test/driver.js.
  Finally, in test/driver.js, we'll now use the PDF.js utility function createObjectURL to get rid of the FileReader usage.

• Convert the writeSVG function, in test/driver.js, to return a Promise

  This allows (some) simplification of the call-sites, since we can now use async/await directly rather than having to manually wrap a lot of code in a Promise.

[pdfjsbot]

From: Bot.io (Windows)

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Received

Command cmd_test from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.193.163.58:8877/543fcfd64ac6d04/output.txt

[pdfjsbot]

From: Bot.io (Linux m4)

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Received

Command cmd_test from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.241.84.105:8877/abced55db150cf5/output.txt

[pdfjsbot]

From: Bot.io (Linux m4)

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Failed

Full output at http://54.241.84.105:8877/abced55db150cf5/output.txt

Total script time: 22.45 mins

• Font tests: Passed
• Unit tests: Passed
• Integration Tests: FAILED
• Regression tests: FAILED

  different ref/snapshot: 7
  different first/second rendering: 1

Image differences available at: http://54.241.84.105:8877/abced55db150cf5/reftest-analyzer.html#web=eq.log

[pdfjsbot]

From: Bot.io (Windows)

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Failed

Full output at http://54.193.163.58:8877/543fcfd64ac6d04/output.txt

Total script time: 43.29 mins

• Font tests: Passed
• Unit tests: Passed
• Integration Tests: FAILED
• Regression tests: FAILED

  different ref/snapshot: 12
  different first/second rendering: 1

Image differences available at: http://54.193.163.58:8877/543fcfd64ac6d04/reftest-analyzer.html#web=eq.log

[Snuffleupagus]

/botio integrationtest

[pdfjsbot]

From: Bot.io (Linux m4)

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Received

Command cmd_integrationtest from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.241.84.105:8877/7732239a02b2e48/output.txt

[pdfjsbot]

From: Bot.io (Windows)

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Received

Command cmd_integrationtest from @Snuffleupagus received. Current queue size: 0

Live output at: http://54.193.163.58:8877/38cf12f042f9f81/output.txt

[pdfjsbot]

From: Bot.io (Linux m4)

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Failed

Full output at http://54.241.84.105:8877/7732239a02b2e48/output.txt

Total script time: 2.53 mins

• Integration Tests: FAILED

[pdfjsbot]

From: Bot.io (Windows)

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Success

Full output at http://54.193.163.58:8877/38cf12f042f9f81/output.txt

Total script time: 6.00 mins

• Integration Tests: Passed

[brendandahl]

Why'd you close this?

[Snuffleupagus]

Why'd you close this?

Because I was getting additional intermittents locally with the latest version of the patch (e.g. in textLayer tests), that I didn't really understand and that didn't really make a lot of sense. Based on that I'm no longer sure if trying to convert everything at once is a good idea, since I really don't want to introduce more intermittent failures in the tests.
Time permitting I'll try to look into this later, but right now I don't think this will work as-is and it does feel somewhat risky (for a small benefit).