The threee tags `<name>`, `</name>` and `<command>` were frequently used
with a leading space that this removes. The reason this habbit is so
widespread in testcases is probably that they have been copy and pasted.
Hence, fixing them all now might curb this practice from now on.
Closes#12028
This test relies on the IPv6 scope field being ignored when connecting to
ipv6-localhost (i.e. [::1%259999] is treated as [::1]). Maybe this is a bit
dodgy, but it works on all our test platforms except Windows. This
test was disabled manually on all Windows CI builds already, so instead
add an incompatible feature and precheck so it's skipped on Windows
everywhere automatically.
