CPP: Add the Semmle security tests.

[geoffw0]

Move the Semmle security tests to public github. With only one or two exceptions, this should give test coverage for all queries in ql\cpp\ql\src\Security.

[jbj]

This appears to add what we want. I note that the tests are passing and that all added files start with cpp/ql/test/query-tests/Security/CWE/CWE-???/semmle/, which as I understand it is the prefix you've used for tests that can be made public. Is there any reason to keep a semmle subdir under all the CWE-??? dirs?

[geoffw0]

which as I understand it is the prefix you've used for tests that can be made public

It's the prefix for tests that [we're sure] were authored by us, so we have no doubt as to our right to distribute them.

Is there any reason to keep a semmle subdir under all the CWE-??? dirs?

Yes, we still have plans to move some of the other subdirs into the public github repo (but we still have some concerns about them, and it's less urgent as they don't tend to be changed as frequently).