There are several locations in the e2e tests where endpoints of the
form IP:port use IPv6 addresses directly, without surrounding brackets.
Brackets are required around IPv6 addresses in this case, in order to
distinguish the colons in the IPv6 address from the colon immediately
preceding the port.

Also, wherever the curl command might be used with an IPv6 address
surrounded in brackets, the "-g" argument is added to the curl
command line arguments so that the brackets can be interpreted
correctly.

fixes #52746