Bug 1687154 - Add raptor's generated files to .gitignore. r=glandium DONTBUILD

Differential Revision: https://phabricator.services.mozilla.com/D102101

.gitignore

@@ -162,3 +162,9 @@ lextab.py
 .vscode/
 !.vscode/extensions.json
 !.vscode/tasks.json
+
+# Ignore various raptor performance framework files
+testing/raptor/.raptor-venv
+testing/raptor/raptor-venv
+testing/raptor/raptor/tests/json/
+testing/raptor/webext/raptor/auto_gen_test_config.js