Bug 1790912 - Fix lint issues in js/ductwork/debugger. r=ochameau

When we move this out of the js/ directory, a number of lint exceptions stop
applying so we should just fix the issues now.

Differential Revision: https://phabricator.services.mozilla.com/D157521

.eslintrc-test-paths.js

@@ -54,6 +54,7 @@ const extraXpcshellTestPaths = [
   "intl/benchmarks/",
   "intl/l10n/test/",
   "ipc/testshell/tests/",
+  "js/ductwork/debugger/tests/",
   "memory/replace/dmd/test/",
   "netwerk/test/httpserver/test/",
   "testing/modules/tests/xpcshell/",