amp-bind: <amp-form> integration test broken on Edge & Safari 9

[camelburrito]

Here is the travis build
https://travis-ci.org/ampproject/amphtml/jobs/240195458

Edge 14.14393.0 (Windows 10 0.0.0) amp-bind with <amp-form> should NOT allow invalid bindings or values FAILED
	Error: timeout of 5000ms exceeded. Ensure the done() callback is being called in this test.
................................
Safari 9.1.2 (Mac OS X 10.11.6) amp-bind with <amp-form> should NOT allow invalid bindings or values FAILED
	timeout of 5000ms exceeded. Ensure the done() callback is being called in this test.

.......
Mobile Safari 9.0.0 (iOS 9.1.0) amp-bind with <amp-form> should NOT allow invalid bindings or values FAILED
	timeout of 5000ms exceeded. Ensure the done() callback is being called in this test.

[camelburrito]

@choumx @cvializ - These tests are blocking the canary , please take a look and skip them if you think its ok to skip or submit fixes/revert them. I would like to make the master green and cut the canary

[dreamofabear]

• Related to amp-bind: Use events to detect template re-render #9725 which un-skips this test.
• This only affects Edge and Safari 9, but is fine on Chrome, Firefox and Safari 10.
• Not caused by a race with AmpFormService registration.
• The Travis logs don't show anything useful.

Reducing priority since master is green now.

[dreamofabear]

Merging with #10053.