[Enhance](regression)Do path creation ahead of time for case test_export_external_table (#28616)

Do path creation ahead of time for case test_export_external_table

regression-test/framework/src/main/groovy/org/apache/doris/regression/suite/Suite.groovy

@@ -575,6 +575,14 @@ class Suite implements GroovyInterceptable {
         Assert.assertEquals(0, code)
     }
 
+    void mkdirRemote(String username, String host, String path) {
+        String cmd = "ssh ${username}@${host} 'mkdir -p ${path}'"
+        logger.info("Execute: ${cmd}".toString())
+        Process process = cmd.execute()
+        def code = process.waitFor()
+        Assert.assertEquals(0, code)
+    }
+
     void sshExec(String username, String host, String cmd) {
         String command = "ssh ${username}@${host} '${cmd}'"
         def cmds = ["/bin/bash", "-c", command]

regression-test/suites/external_table_p0/export/test_export_external_table.groovy

@@ -55,12 +55,22 @@ suite("test_export_external_table", "p0,external,mysql,external_docker,external_
     }
 
     def check_path_exists = { dir_path ->
+        List<List<Object>> backends =  sql """ show backends """
+        assertTrue(backends.size() > 0)
         File path = new File(dir_path)
         if (!path.exists()) {
             assert path.mkdirs()
         } else {
             throw new IllegalStateException("""${dir_path} already exists! """)
         }
+        if (backends.size() > 1) {
+            for (List<Object> backend : backends) {
+                def be_host = backend[1]
+                def cmd="""mkdir -p ${dir_path}"""
+                sshExec("root", be_host, cmd.toString())
+            }
+        }
+
     }
     def check_file_amounts = { dir_path, amount ->
         File path = new File(dir_path)