Re-evaluate predicate in FnCondition.whenReadyIf as the predicate may have changed while awaiting the condition (#502)

Author: ginkel

java-client/src/main/java/co/elastic/clients/elasticsearch/_helpers/bulk/FnCondition.java

@@ -81,6 +81,11 @@ public <T> T whenReadyIf(BooleanSupplier canRun, Supplier<T> fn) {
                 }
                 condition.awaitUninterruptibly();
             }
+
+            if (canRun != null && !canRun.getAsBoolean()) {
+                return null;
+            }
+
             return fn.get();
         } finally {
             lock.unlock();