chore: upgrade testbench to 9.4.0 (#7596)

Author: ZheSun88

pom.xml

@@ -69,7 +69,7 @@
     </scm>
     <properties>
         <flow.version>25.0-SNAPSHOT</flow.version>
-        <testbench.version>9.4.0.rc1</testbench.version>
+        <testbench.version>9.4.0</testbench.version>
         <maven.compiler.source>17</maven.compiler.source>
         <maven.compiler.target>17</maven.compiler.target>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>