Use double quotes instead of single ones which make the test fail on Windows....

Use double quotes instead of single ones which make the test fail on Windows. This is for bug #30164.

mysql-test/t/mysql.test

@@ -276,6 +276,6 @@ EOF
 #
 # bug #30164: Using client side macro inside server side comments generates broken queries
 #
---exec $MYSQL test -e '/*! \C latin1 */ select 1;'
+--exec $MYSQL test -e "/*! \C latin1 */ select 1;"
 
 --echo End of 5.0 tests