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
are not, due mainly to the lack of support for XML character entities
(e.g. & => & ). This will make it easier to validate test files using
tools like xmllint, as well as edit and view them using XML tools.