Test routing of URLs with special characters

Previously gorouter changed the encoding of some of these values while proxying, now
gorouter should send the exact same encoding to the backend as the original client sent
to gorouter. (In other words, whatever the client sends is what the app running on the
DEA should receive).

[#77014252]

Signed-off-by: Michael Fraenkel <fraenkel@us.ibm.com>