Restore AnalysisModuleTests#testStandardFilterBWC (#119060)

This test has been removed with #112570 but with
the coming read-only support for v7 we need it back.

Author: cbuescher

server/src/test/java/org/elasticsearch/indices/analysis/AnalysisModuleTests.java

@@ -22,6 +22,7 @@
 import org.elasticsearch.index.IndexService.IndexCreationContext;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.IndexVersion;
+import org.elasticsearch.index.IndexVersions;
 import org.elasticsearch.index.analysis.Analysis;
 import org.elasticsearch.index.analysis.AnalysisRegistry;
 import org.elasticsearch.index.analysis.CharFilterFactory;
@@ -186,6 +187,34 @@ public void testUnderscoreInAnalyzerName() throws IOException {
         }
     }
 
+    public void testStandardFilterBWC() throws IOException {
+        // standard tokenfilter should have been removed entirely in the 7x line. However, a
+        // cacheing bug meant that it was still possible to create indexes using a standard
+        // filter until 7.6
+        {
+            IndexVersion version = IndexVersionUtils.randomVersionBetween(random(), IndexVersions.V_7_6_0, IndexVersion.current());
+            final Settings settings = Settings.builder()
+                .put("index.analysis.analyzer.my_standard.tokenizer", "standard")
+                .put("index.analysis.analyzer.my_standard.filter", "standard")
+                .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
+                .put(IndexMetadata.SETTING_VERSION_CREATED, version)
+                .build();
+            IllegalArgumentException exc = expectThrows(IllegalArgumentException.class, () -> getIndexAnalyzers(settings));
+            assertThat(exc.getMessage(), equalTo("The [standard] token filter has been removed."));
+        }
+        {
+            IndexVersion version = IndexVersionUtils.randomVersionBetween(random(), IndexVersions.V_7_0_0, IndexVersions.V_7_5_2);
+            final Settings settings = Settings.builder()
+                .put("index.analysis.analyzer.my_standard.tokenizer", "standard")
+                .put("index.analysis.analyzer.my_standard.filter", "standard")
+                .put(Environment.PATH_HOME_SETTING.getKey(), createTempDir().toString())
+                .put(IndexMetadata.SETTING_VERSION_CREATED, version)
+                .build();
+            getIndexAnalyzers(settings);
+            assertWarnings("The [standard] token filter is deprecated and will be removed in a future version.");
+        }
+    }
+
     /**
      * Tests that plugins can register pre-configured char filters that vary in behavior based on Elasticsearch version, Lucene version,
      * and that do not vary based on version at all.