RelocationTools.revertRouting does not really revert

[eddieh-xlnx]

https://github.com/Xilinx/RapidWright/blob/a34c0d71521a758e757056714ff0503de28f0c71/src/com/xilinx/rapidwright/design/tools/RelocationTools.java#L304-L308

is effectively a NOOP because it's modifying the list of references (to the same set of references) but not actually changing the referent.