Web Platform spec needs some love (when shim is required).

[vicb]

I had to disable some tests for browsers that require the shim.

This has been done in #1288

@vsavkin suggested to re-enable tests but it makes tests fail.

Someone should look at this, preferably @vsavkin or @jbdeboer as I think they both have worked on this code.

[naomiblack]

@vsavkin please take a look and see if this is still current and update the bug and milestone.

[vsavkin]

The issue is still present. The disabled tests fail in IE10.