When you get an infinite loop in jsfiddle in Chrome, your only choice (that I know of) is to close the tab. Of course, this means you lose all your work in the current wind
I couldn't start Chrome's Task Manager while the looping tab was active. I had to select another tab. Then I pressed Shift-Escape to launch the Task Manager, kill the JSFiddle process, re-select the tab, and hit the back button to display the page without running the script.
JSFiddle loads the "result" panel using an iframe. As of June 2016, the URL for the frame is the Fiddle URL plus "/show/". I inspected the source code of the iframe and discovered that it loads yet another URL with "/light/". One of these URLs should contain your source code.
If your browser supports the view-source URI scheme, you may access your fiddle's source code as follows: