Add entries to .gitignore of stable-3.0 that exist on master

Change-Id: I2f6e5f89b209c3d10048e72fa7aee5ea6fb0a319
diff --git a/.gitignore b/.gitignore
index 93c1339..94d78c4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -18,6 +18,7 @@
 /.settings/org.eclipse.ltk.core.refactoring.prefs
 /.settings/org.eclipse.m2e.core.prefs
 /.settings/org.maven.ide.eclipse.prefs
+/.ts-out
 /.vscode
 /bazel-*
 /bin/
@@ -45,3 +46,5 @@
 !/plugins/webhooks
 /test_site
 /tools/format
+/tools/node_tools
+/tools/polygerrit-updater