Try to fix flacky tests

Author: ianton-ru

tests/integration/test_s3_cluster/test.py

@@ -1049,6 +1049,7 @@ def test_joins(started_cluster):
     node = started_cluster.instances["s0_0_0"]
 
     # Table join_table only exists on the node 's0_0_0'.
+    node.query("DROP TABLE IF EXISTS join_table SYNC")
     node.query(
         """
         CREATE TABLE IF NOT EXISTS join_table (

tests/integration/test_storage_iceberg/test.py

@@ -3446,6 +3446,10 @@ def execute_spark_query(query: str):
 
     # Warm up metadata cache
     for replica in started_cluster.instances.values():
+        replica.query("SYSTEM DROP UNCOMPRESSED CACHE")
+        replica.query("SYSTEM DROP QUERY CACHE")
+        replica.query("SYSTEM DROP FILESYSTEM CACHE")
+        replica.query("SYSTEM DROP ICEBERG METADATA CACHE")
         replica.query(f"SELECT * FROM {creation_expression} ORDER BY ALL SETTINGS allow_experimental_iceberg_read_optimization=0")
 
     all_data_expected_query_id = str(uuid.uuid4())