Fix testValidFromPattern (#121996)

Author: idegtiarenko

muted-tests.yml

@@ -397,9 +397,6 @@ tests:
   issue: https://github.com/elastic/elasticsearch/issues/121966
 - class: org.elasticsearch.xpack.searchablesnapshots.hdfs.SecureHdfsSearchableSnapshotsIT
   issue: https://github.com/elastic/elasticsearch/issues/121967
-- class: org.elasticsearch.xpack.esql.parser.StatementParserTests
-  method: testInvalidJoinPatterns
-  issue: https://github.com/elastic/elasticsearch/issues/121968
 - class: org.elasticsearch.smoketest.SmokeTestMultiNodeClientYamlTestSuiteIT
   method: test {yaml=update/100_synthetic_source/stored text}
   issue: https://github.com/elastic/elasticsearch/issues/121991

x-pack/plugin/esql/src/test/java/org/elasticsearch/xpack/esql/IdentifierGenerator.java

@@ -78,16 +78,17 @@ public static String randomIndexPattern(Feature... features) {
             index.insert(0, "-");
         }
 
-        var pattern = maybeQuote(index.toString());
+        var pattern = index.toString();
+        if (pattern.contains("|")) {
+            pattern = quote(pattern);
+        }
+        pattern = maybeQuote(pattern);
+
         if (canAdd(Features.CROSS_CLUSTER, features)) {
             var cluster = maybeQuote(randomIdentifier());
             pattern = maybeQuote(cluster + ":" + pattern);
         }
 
-        if (pattern.contains("|") && pattern.contains("\"") == false) {
-            pattern = quote(pattern);
-        }
-
         return pattern;
     }