Fix xfail-license files

[brson]

Files containing xfail-license have unclear licenses. In most cases it should just be a matter of confirming that the developer(s) contributed the code using our license (we have many such statements on file), and adding the standard license block. They are mostly just oversights.

[emberian]

Still relevant, mostly in the ARM C++ rt and for various scripts that use a license format it doesn't recognize.

[thestinger]

There are still 20 of these files to deal with.

[adrientetar]

@brson Can you ack #11989?

[brson]

Glad to see this closed.