MDEV-10411 Providing compatibility for basic PL/SQL constructs

- Part 9: EXCEPTION handlers

  The top-most stored routine blocks now support EXCEPTION clause
  in its correct place:
  AS [ declarations ]
  BEGIN statements
  [ EXCEPTION exceptions ]
  END

  Inner block will be done in a separate commit.

- Part 14: IN OUT instead of INOUT (in SP parameter declarations)

sql/sql_lex.h

@@ -3145,6 +3145,11 @@ public:
     res->join(b1, b2);
     return false;
   }
+  bool sp_block_with_exceptions_finalize_declarations(THD *thd);
+  bool sp_block_with_exceptions_finalize_executable_section(THD *thd,
+                                                  uint executable_section_ip);
+  bool sp_block_with_exceptions_finalize_exceptions(THD *thd,
+                                                  uint executable_section_ip);
   // Check if "KEY IF NOT EXISTS name" used outside of ALTER context
   bool check_add_key(DDL_options_st ddl)
   {