remove redundant instanceof check

Co-authored-by: Esben Sparre Andreasen <[email protected]>

Author: erik-krogh

javascript/ql/src/semmle/javascript/Promises.qll

@@ -327,7 +327,6 @@ private module PromiseFlow {
       pred = promise.getValue() and
       succ = this
       or
-      promise instanceof PromiseAllCreation and
       prop = valueProp() and
       pred = promise.(PromiseAllCreation).getArrayNode() and
       succ = this