Bug 1333423 - multiProcessCompatible=false should always be honored. r=felipe

toolkit/mozapps/extensions/internal/E10SAddonsRollout.jsm

@@ -938,11 +938,11 @@ Object.defineProperty(this, "isAddonPartOfE10SRollout", {
 
     let policy = RolloutPolicy[policyId];
 
-    if (policy.alladdons) {
-      if (aAddon.mpcOptedOut == true) {
-        return false;
-      }
+    if (aAddon.mpcOptedOut == true) {
+      return false;
+    }
 
+    if (policy.alladdons) {
       return true;
     }