MXS-1196: Add Oracle specific tests

Copied from .../server/mysql-test/suite/compat/oracle/t

Will be used as a baseline and edited as needed.

query_classifier/test/oracle/variables.test

@@ -0,0 +1,38 @@
+SET sql_mode=oracle;
+
+--echo #
+--echo # MDEV-10411 Providing compatibility for basic PL/SQL constructs
+--echo # Part 6: Assignment operator
+--echo #
+
+max_sort_length:=1030;
+SELECT @@max_sort_length;
+max_sort_length:=DEFAULT;
+
+--echo #
+--echo # Testing that SP variables shadow global variables in assignments
+--echo #
+
+DELIMITER $$;
+CREATE PROCEDURE p1
+AS
+BEGIN
+  max_sort_length:=1030;
+  DECLARE
+    max_sort_length INT DEFAULT 1031;
+  BEGIN
+    SELECT @@max_sort_length, max_sort_length;
+    max_sort_length:=1032;
+    SELECT @@max_sort_length, max_sort_length;
+  END;
+  SELECT @@max_sort_length;
+  max_sort_length:= DEFAULT;
+END;
+$$
+DELIMITER ;$$
+CALL p1();
+DROP PROCEDURE p1;
+
+--echo #
+--echo # End of MDEV-10411 Providing compatibility for basic PL/SQL constructs (part 6)
+--echo #