Replace tika-files.zip by a tika-files dir

Let's make our life easier when debugging/testing.
Also having a flat dir helps us to compare or "synchronize" more easily with Tika project files.

Closes #22958.

Backport of #22959 in 5.2 branch

Author: dadoonet

plugins/ingest-attachment/src/test/java/org/elasticsearch/ingest/attachment/TikaDocTests.java

@@ -22,11 +22,13 @@
 import org.apache.lucene.util.LuceneTestCase.SuppressFileSystems;
 import org.apache.lucene.util.TestUtil;
 import org.apache.tika.metadata.Metadata;
+import org.elasticsearch.common.io.PathUtils;
 import org.elasticsearch.test.ESTestCase;
 
 import java.nio.file.DirectoryStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.Paths;
 
 /**
  * Evil test-coverage cheat, we parse a bunch of docs from tika
@@ -37,11 +39,17 @@
 public class TikaDocTests extends ESTestCase {
 
     /** some test files from tika test suite, zipped up */
-    static final String TIKA_FILES = "/org/elasticsearch/ingest/attachment/test/tika-files.zip";
+    static final String TIKA_FILES = "/org/elasticsearch/ingest/attachment/test/tika-files/";
 
     public void testFiles() throws Exception {
         Path tmp = createTempDir();
-        TestUtil.unzip(getClass().getResourceAsStream(TIKA_FILES), tmp);
+        logger.debug("unzipping all tika sample files");
+        try (DirectoryStream<Path> stream = Files.newDirectoryStream(PathUtils.get(getClass().getResource(TIKA_FILES).toURI()))) {
+            for (Path doc : stream) {
+                String filename = doc.getFileName().toString();
+                TestUtil.unzip(getClass().getResourceAsStream(TIKA_FILES + filename), tmp);
+            }
+        }
 
         try (DirectoryStream<Path> stream = Files.newDirectoryStream(tmp)) {
             for (Path doc : stream) {