Tests that src and href element targets are rewritten properly.

TEST ENDED IN ERROR: TypeError: Cannot read property 'nodeType' of null
    at Elements.ElementsTreeOutline.findTreeElement (file:///b/s/w/ir/out/Release/resources/inspector/elements/elements_module.js:508:91)
    at Elements.ElementsTreeOutline._innerUpdateChildren (file:///b/s/w/ir/out/Release/resources/inspector/elements/elements_module.js:674:177)
    at Elements.ElementsTreeOutline._updateChildren (file:///b/s/w/ir/out/Release/resources/inspector/elements/elements_module.js:664:50)
    at Elements.ElementsTreeOutline._updateModifiedParentNode (file:///b/s/w/ir/out/Release/resources/inspector/elements/elements_module.js:633:6)
    at Elements.ElementsTreeOutline._updateModifiedNodes (file:///b/s/w/ir/out/Release/resources/inspector/elements/elements_module.js:625:6)