Add .apt_generated_tests to .gitignore

Change-Id: I1975da67be6268189c3875acfbb5dd6e33e6eee6
diff --git a/.gitignore b/.gitignore
index 5fdc85b..e544356 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,6 +8,7 @@
 .DS_Store
 .gwt_work_dir
 /.apt_generated
+/.apt_generated_tests
 /.bazel_path
 /.buckd
 /.classpath