Prevent infinite loop with AbstractCharacterFilterReader if EOF is filtered out

[robtimus]

AbstractCharacterFilterReader.read() only aborts its loop if filter(ch) returns false. If that method returns true for EOF, you'll get an infinite loop if the backing read() call keeps returning EOF. That's really easy to achieve with CharacterFilterReader.

This small fix aborts the loop not only if filter(ch) returns false, but also if the backing read() call returns EOF.

[coveralls]

Coverage remained the same at 89.26% when pulling 153f3d1 on robtimus:infinite-loop-AbstractCharacterFilterReader into 8365dcf on apache:master.

[garydgregory]

@robtimus
I pushed an alternate commit to master, please verify and close this PR if it works for you.

[robtimus]

@garydgregory
Thanks, the only difference between this PR and master is now a (duplicated) test.

[garydgregory]

What is duplicated?

[robtimus]

I had added the testReadFilteringEOF method at the bottom, whereas you added it a bit higher. That didn't trigger any conflicts during rebase, it just added the same method, leading to two methods with the same name and almost the same contents.