perf[storage]: use string as cache to reduce memory consumption

storage/src/test/java/com/zfoo/storage/util/FieldUtilsTest.java

@@ -20,7 +20,7 @@ import static org.junit.Assert.assertEquals;
 /**
  * @author veione
  */
-public class TestFieldUtils {
+public class FieldUtilsTest {
 
     @Test
     public void testPropertyName() {

storage/src/test/java/com/zfoo/storage/util/LambdaFunctionCacheTest.java

@@ -19,7 +19,7 @@ import org.junit.Test;
 /**
  * @author veione
  */
-public class TestLambdaFunctionCache {
+public class LambdaFunctionCacheTest {
 
     @Test
     public void testFunctionCache() {

storage/src/test/java/com/zfoo/storage/util/LambdaFunctionTest.java

@@ -23,7 +23,7 @@ import java.lang.reflect.Method;
 /**
  * @author veione
  */
-public class TestLambdaFunction {
+public class LambdaFunctionTest {
     //https://blog.csdn.net/iteye_19045/article/details/119299015
     @Test
     public void testFuncSerialization() throws Exception {