Get rid of double executor in retrying

Closes #382

Author: ArtDu

src/main/java/io/tarantool/driver/core/RetryingTarantoolClient.java

@@ -440,8 +440,12 @@ private <S> CompletableFuture<S> wrapOperation(Supplier<CompletableFuture<S>> op
 
     private TarantoolSpaceOperations<T, R> getTarantoolSpaceOperationsRetrying(
         Supplier<TarantoolSpaceOperations<T, R>> spaceSupplier) {
+        CompletableFuture<TarantoolSpaceOperations<T, R>> wrapperForSync = new CompletableFuture<>();
         try {
-            return wrapOperation(() -> CompletableFuture.supplyAsync(spaceSupplier, executor)).get();
+            return wrapOperation(() -> {
+                wrapperForSync.complete(spaceSupplier.get());
+                return wrapperForSync;
+            }).get();
         } catch (InterruptedException e) {
             throw new CompletionException(e);
         } catch (ExecutionException e) {