🐛Flaky tests in test-resources.js

[calebcordry]

Several tests in this file are flaking with no immediately obvious pattern.

Some examples:
https://travis-ci.org/ampproject/amphtml/jobs/391329023 (this is the most frequent)
https://travis-ci.org/ampproject/amphtml/jobs/391379325
https://travis-ci.org/ampproject/amphtml/jobs/391742459

[calebcordry]

cc/ @rsimha

[calebcordry]

I thought this was the same as the first link, but it is actually slightly different:
https://travis-ci.org/ampproject/amphtml/jobs/391544247

[dreamofabear]

DESCRIBE => Resources discoverWork
  IT => "after each" hook for "should update inViewport before scheduling layouts"
    ✗ Unexpected call: getRect() at setState@/tmp/src/finite-state-machine.js:73:6 <- /tmp/5c710cc6478d2b0f6baf816fd1c218c5.browserify:66544:15
    Unexpected call: getRect() at setState@/tmp/src/finite-state-machine.js:73:6 <- /tmp/5c710cc6478d2b0f6baf816fd1c218c5.browserify:66544:15
    Unexpected call: getRect() at setState@/tmp/src/finite-state-machine.js:73:6 <- /tmp/5c710cc6478d2b0f6baf816fd1c218c5.browserify:66544:15

DESCRIBE => Resources changeSize
  DESCRIBE => attemptChangeSize rules wrt viewport
    IT => should change size when document is invisible
      ✗ Attempted to wrap getVisibilityState which is already wrapped

  IT => "after each" hook for "should change size when document is invisible"
    ✗ Expected getRect([...]) at least once (never called)

IT => "after each" hook for "should change size when document is invisible"
  ✗ You likely forgot to restore sinon timers (installed via sandbox.useFakeTimers).

[16:10:03] Safari 11.1.0 (Mac OS X 10.13.4): Executed 1750 of 3595 (Skipped 174) 4 FAILED

I think this started getting more flaky on Safari 11.1.

[dreamofabear]

/cc @jridgewell

[ampprojectbot]

This issue hasn't been updated in awhile. @jridgewell Do you have any updates?

[dreamofabear]

Closing as dupe of #16124.