include java/ files in output if they are targeted

[theron-wang]

In na-97, where we target a java/ file, the targeted file (java/util/atomic/concurrent/Striped64.java, I believe) was being excluded from the output because of these lines in SpeciminRunner:

if (target.getKey().startsWith("java/")) {
    continue;
}

The reason it worked on Windows was probably because Windows uses backslashes, and it didn't work on Unix because of the forward slash comparison here. I changed it so that the target file is preserved in the output no matter what, even if it starts with java/ (or java\). This should make na-97 work on both OSes.

I didn't include a test case for this, since NullAway bugs are now in the evaluation script, but if you'd like, I could add one. Thanks!

[kelloggm]

CI should fail on this change, since we expect it to fix na-97 but it doesn't change the preservation status file. That will be a good test of the updated CI.

[theron-wang]

Whoops, I think I have to merge the latest changes first.