[FEATURE query-params-new] Fix failures in IE8.

IE8 does not allow `String.substr` to accept negative values. Replacing
with `slice` works well.

@raytiley / @rjackson
[FEATURE query-params-new] Fix issue with tests in IE8.

`DOMElem.classList` does not exist in IE8.

@raytiley / @rjackson
Merge pull request #4244 from rjackson/fix-qpn-in-ie8

[FEATURE query-params-new] Fix failures in IE8.