Fix flaky testOverflowDisabledAsynchronous by throwing AlreadyClosedException (#20848)

When the file cache is full and a blob fetch races with cache eviction,
DelayedCreationCachedIndexInput.getIndexInput() throws an
IllegalStateException, so this surfaces as an IllegalStateException
instead of the IOException callers expect. Replace IllegalStateException
with Lucene's AlreadyClosedException (which extends IOException) in both
getIndexInput() and asyncLoadIndexInput().

Signed-off-by: Andrew Ross <andrross@amazon.com>

Author: andrross

server/src/main/java/org/opensearch/index/store/remote/utils/TransferManager.java

@@ -10,6 +10,7 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexInput;
 import org.opensearch.common.annotation.ExperimentalApi;
@@ -206,7 +207,7 @@ private DelayedCreationCachedIndexInput(FileCache fileCache, StreamReader stream
         @Override
         public IndexInput getIndexInput() throws IOException {
             if (isClosed.get()) {
-                throw new IllegalStateException("Already closed");
+                throw new AlreadyClosedException("Already closed");
             }
             if (isStarted.getAndSet(true) == false) {
                 // We're the first one here, need to download the block
@@ -233,7 +234,7 @@ public IndexInput getIndexInput() throws IOException {
         public CompletableFuture<IndexInput> asyncLoadIndexInput(Executor executor) {
             if (isClosed.get()) {
                 fileCache.decRef(request.getFilePath());
-                return CompletableFuture.failedFuture(new IllegalStateException("Already closed"));
+                return CompletableFuture.failedFuture(new AlreadyClosedException("Already closed"));
             }
             if (isStarted.getAndSet(true) == false) {
                 // Create new future and set it as the result