* Add tests/std.
* Update other files.
NOTICE.txt
Mention the LLVM Project, as its code appears
in tests/std/tests/P0220R1_optional/test.cpp and elsewhere.
azure-devops/enforce-clang-format.cmd
Process everything within tests. This includes libcxx, std, and tr1.
docs/cgmanifest.json
Update this file for Microsoft-internal purposes. (It records the commit
hashes of repos whose source code we've incorporated into our own repo.
For llvm-project, this is distinct from the submodule's current commit.)
tests/tr1/run.pl
Mention runbe.pl in lowercase, to match the file itself.
* Improve run.pl and runbe.pl comments.