Update .gitignore with test/test262-es6/data.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/646933002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24515 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

.gitignore

@@ -61,6 +61,9 @@ shell_g
 /test/test262/data
 /test/test262/data.old
 /test/test262/tc39-test262-*
+/test/test262-es6/data
+/test/test262-es6/data.old
+/test/test262-es6/tc39-test262-*
 /testing/gmock
 /testing/gtest
 /third_party/icu