Bug 1522830: Part 3 - Change launcher blocklist generation to include child processes; r=bytesized

Now that the launcher blocklist will support child processes, we need to add
them to the launcher blocklist. The revised criteria the `Launcher` blocklist
matches the criteria already in use by the `Legacy` blocklist.

Differential Revision: https://phabricator.services.mozilla.com/D53675

--HG--
extra : moz-landing-system : lando

mozglue/dllservices/gen_dll_blocklist_defs.py

@@ -358,7 +358,8 @@ GENERATED_BLOCKLIST_FILES = [
     # Child is not used by anything at the moment, so we'll just leave this
     # descriptor commented out for now.
     # BlocklistDescriptor('Child', ['ALL_PROCESSES', 'CHILD_PROCESSES']),
-    BlocklistDescriptor('Launcher', ['ALL_PROCESSES', 'BROWSER_PROCESS']),
+    BlocklistDescriptor('Launcher', ALL_DEFINITION_LISTS, flagspec={
+                        'CHILD_PROCESSES': {CHILD_PROCESSES_ONLY}}),
     BlocklistDescriptor('Legacy', ALL_DEFINITION_LISTS, flagspec={
                         'CHILD_PROCESSES': {CHILD_PROCESSES_ONLY}}),
     # Roughed-in for the moment; we'll enable this in bug 1238735