Remove an IE7 hack

[NattyNarwhal]

No description provided.

[martinwoodward]

While I'm not that bothered about IE7 support myself, I don't think we need to remove support for it now do we? What was the motivation for removing the code?

[NattyNarwhal]

None of the supported platforms can run IE 7 (let alone a prelease version) - in addition, it's legacy code, which muddles understanding, wastes resources, and can get in the way of further improvements..

[ScottIsAFool]

Is it confirmed that the hack is no longer necessary?

[NattyNarwhal]

I did some quick tests and it seems fine to me. If there's a bug on the IE end, it should have been solved by IE 7 RTM at least.

[ScottIsAFool]

That's fine then.

[kathweaver]

From @ScottIsAFool on another one: We have moved to the dotnetfoundation's AppVeyor account and ScottH has closed his account which is what we used to be using. If @vhanla were to make an arbitrary commit to this branch and push it, it would force a rebuild on appveyor.

[RobDolinMS]

Merging this could be risky if a user has IE in a legacy compatibility mode.
It would be great to get more testing on this.

[dnfclas]

@NattyNarwhal, Thanks for signing the contribution license agreement so quickly! Actual humans will now validate the agreement and then evaluate the PR.

Thanks, DNFBOT;