Add more async code when loading fonts in the PartialEvaluator

[Snuffleupagus]

No description provided.

[timvandermeij]

r=me with passing tests; thank you!

[timvandermeij]

/botio test

[moz-tools-bot]

From: Bot.io (Linux m4)

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Received

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

Live output at: http://54.241.84.105:8877/d43c6cab4fec42a/output.txt

[moz-tools-bot]

From: Bot.io (Windows)

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Received

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

Live output at: http://54.193.163.58:8877/7a955cebb9e9958/output.txt

[moz-tools-bot]

From: Bot.io (Linux m4)

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Failed

Full output at http://54.241.84.105:8877/d43c6cab4fec42a/output.txt

Total script time: 24.76 mins

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

  different ref/snapshot: 17
  different first/second rendering: 2

Image differences available at: http://54.241.84.105:8877/d43c6cab4fec42a/reftest-analyzer.html#web=eq.log

[moz-tools-bot]

From: Bot.io (Windows)

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Failed

Full output at http://54.193.163.58:8877/7a955cebb9e9958/output.txt

Total script time: 38.08 mins

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

  different ref/snapshot: 22

Image differences available at: http://54.193.163.58:8877/7a955cebb9e9958/reftest-analyzer.html#web=eq.log

[timvandermeij]

/botio-windows integrationtest

[moz-tools-bot]

From: Bot.io (Windows)

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Received

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

Live output at: http://54.193.163.58:8877/9d55aea115b9aed/output.txt

[moz-tools-bot]

From: Bot.io (Windows)

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Success

Full output at http://54.193.163.58:8877/9d55aea115b9aed/output.txt

Total script time: 17.99 mins

• Integration Tests: Passed