Copy all SVG child nodes when using setting innerHTML in IE

[zpao]

This is a followup to #6982, which missed half the nodes. We missed this because the test that was written depended on broken JSDOM behavior (will report shortly).

Test Plan:

• https://jsfiddle.net/ra8xrruh/1/ is broken in IE11 (currently using 15.3.1) - only see every other bar.
• http://playground.zpao.com/tmp/react_7358/ works (same code, patch applied, on master)

I also renamed the test file to fit our convention.

[sophiebits]

I hope this isn't n^2 in some browsers.

[sophiebits]

Thanks.