Delete CalcitePushdownIT since all tests are run with pushdown enabled by default

Signed-off-by: Yuanchun Shen <yuanchu@amazon.com>

Author: yuancu

integ-test/src/test/java/org/opensearch/sql/calcite/pushdown/CalciteNoPushdownIT.java

@@ -14,6 +14,11 @@
 import org.opensearch.sql.calcite.remote.*;
 import org.opensearch.sql.ppl.PPLIntegTestCase;
 
+/**
+ * This test suite runs all remote Calcite integration tests without pushdown enabled.
+ *
+ * <p>Individual tests in this suite will be executed independently with pushdown enabled.
+ */
 @RunWith(Suite.class)
 @Suite.SuiteClasses({
   CalciteArrayFunctionIT.class,