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 is already how curl is documented to behave in Everything curl, but
in actuality only short POSTs skip this. This should knock 30 seconds
off a full run of the test suite since the 100-continue timeout will no
longer be hit.
Closes#10740
