lib: move deprecationWarned var

The variable deprecationWarned currently looks a little misplaced. It is
used in emitWarning but declared after it. This commit suggest moving
the var to the beginning of the function.

PR-URL: nodejs#14769
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Alexey Orlenko <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Tobias Nießen <[email protected]>
Reviewed-By: Refael Ackermann <[email protected]>
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: James M Snell <[email protected]>

lib/internal/process/promises.js

@@ -14,6 +14,8 @@ function getAsynchronousRejectionWarningObject(uid) {
 }
 
 function setupPromises(scheduleMicrotasks) {
+  let deprecationWarned = false;
+
   process._setupPromises(function(event, promise, reason) {
     if (event === promiseRejectEvent.unhandled)
       unhandledRejection(promise, reason);
@@ -73,7 +75,7 @@ function setupPromises(scheduleMicrotasks) {
         'DeprecationWarning', 'DEP0018');
     }
   }
-  var deprecationWarned = false;
+
   function emitPendingUnhandledRejections() {
     let hadListeners = false;
     while (pendingUnhandledRejections.length > 0) {