Remove deprecation log file check in 6.8 (#67465)

This test has been muted for a very long time, yet the underlying cause
is still unknown, but it only occurs in 6.8. This commit removes the
failing portion of the test so that we have some coverage.

closes #35990

Author: rjernst

qa/evil-tests/src/test/java/org/elasticsearch/common/logging/EvilLoggerTests.java

@@ -253,7 +253,6 @@ public void testDeprecationLoggerMaybeLog() throws IOException, UserException {
         }
     }
 
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/35990")
     public void testDeprecatedSettings() throws IOException, UserException {
         setupLogging("settings");
 
@@ -266,21 +265,9 @@ public void testDeprecatedSettings() throws IOException, UserException {
             assertSettingDeprecationsAndWarnings(new Setting<?>[]{setting});
         }
 
-        final String deprecationPath =
-                System.getProperty("es.logs.base_path") +
-                        System.getProperty("file.separator") +
-                        System.getProperty("es.logs.cluster_name") +
-                        "_deprecation.log";
-        final List<String> deprecationEvents = Files.readAllLines(PathUtils.get(deprecationPath));
-        if (iterations > 0) {
-            assertThat(deprecationEvents.size(), equalTo(1));
-            assertLogLine(
-                    deprecationEvents.get(0),
-                    Level.WARN,
-                    "org.elasticsearch.common.logging.DeprecationLogger.deprecated",
-                    "\\[deprecated.foo\\] setting was deprecated in Elasticsearch and will be removed in a future release! " +
-                            "See the breaking changes documentation for the next major version.");
-        }
+        // We SHOULD check the log message actually made it to the deprecation log (and we do
+        // in newer branches), but on 6.8 it is somehow possible the log is not flushed.
+        // See https://github.com/elastic/elasticsearch/issues/35990
     }
 
     public void testFindAppender() throws IOException, UserException {