node tests: Just set i18n every time.

Explicitly stubbing i18n in 48 different files
is mostly busy work at this point, and it doesn't
provide much signal, since often it's invoked
only to satisfy transitive dependencies.

frontend_tests/node_tests/stream_sort.js

@@ -1,4 +1,3 @@
-set_global('i18n', global.stub_i18n);
 
 zrequire('stream_data');
 zrequire('stream_sort');