[fix](env)mock env.isCheckpointThread apache#24280

ssue Number: close #xxx

ShowTableStmtTest.testNoDb and DropDbStmtTest.testNoPriv are unstable cases，error msg is:

java.lang.Exception: Unexpected exception, expected<org.apache.doris.common.AnalysisException> but was<mockit.internal.expectations.invocation.MissingInvocation>
reason is missing mock env.isCheckpointThread

fe/fe-core/src/test/java/org/apache/doris/analysis/AccessTestUtil.java

@@ -418,6 +418,10 @@ public static Env fetchBlockCatalog() {
                     env.getCatalogMgr();
                     minTimes = 0;
                     result = ctlMgr;
+
+                    env.isCheckpointThread();
+                    minTimes = 0;
+                    result = false;
                 }
             };
             return env;