improve sql parser & improve GetConnecitonTimeout error message

src/test/java/com/alibaba/druid/sql/JSqlParserTest.java

@@ -0,0 +1,16 @@
+package com.alibaba.druid.sql;
+
+import java.io.StringReader;
+
+import junit.framework.TestCase;
+import net.sf.jsqlparser.parser.CCJSqlParserManager;
+
+public class JSqlParserTest extends TestCase {
+    CCJSqlParserManager parserManager = new CCJSqlParserManager();
+    
+    public void test_0() throws Exception {
+        String statement = "ALTER TABLE `test`.`tb1`  ADD INDEX `ix` (`f2` ASC) ;";
+        
+        parserManager.parse(new StringReader(statement));
+    }
+}