Added missing test files for rwsplit router tests.

server/modules/routing/readwritesplit/test/test_transaction_routing3b.sql

@@ -0,0 +1,7 @@
+-- Read from slave after implicit COMMIT
+USE test; 
+START TRANSACTION; 
+CREATE TABLE IF NOT EXISTS T2 (id integer); 
+INSERT INTO T2 VALUES (@@server_id);
+SET AUTOCOMMIT=oN;
+SELECT id from T2; -- read transaction's modifications from slave