Garbage left in source tree after SQL tests are run

Don't know when this started, but after I run tests in sbt I'm left with garbage files in my source repo:

Untracked files:
  (use "git add <file>..." to include in what will be committed)

        sql/core/%253Cundefined%253E/
        sql/core/%3Cundefined%3E/

Tests should always write things under the "target" directory so that it gets automatically ignored by git and cleaned up by "sbt/mvn clean."