There's a bunch of font directories inside of test/ for which the vast
majority of fonts are licensed under the SIL open font license. We currently
have a COPYING file in test/shape/data/in-house/COPYING that says that most
of the fonts are OFL-1.1, but that doesn't apply to the fonts in, say,
test/api/fonts/ or test/fuzzing/fonts/. Since there are so many OFL-1.1
fonts all over test, let's move the COPYING file to the top-level test/
directory.