WL6384 provides new DD tables ("Routines" and "Parameters") and
new DD APIs to work with the stored routines(Stored function and
procedures).

This patch mainly uses APIs provided by WL6384 to store, drop,
alter routine metadata in New DD tables and read stored routine's
metadata from new DD tables("Routines" and "Parameters").
Table mysql.proc creation and usage is avoided with this patch.

A) As part of this WL, followings APIs are introduced to operate
   on new DD tables using DD APIs. These methods are called by the
   current SP module.

    a) template <typename T>
       enum_sp_return_code dd::create_routine(...)

       Stores metadata information from sp_head object to the DD
       tables.

    b) template <typename T>
       enum_sp_return_code dd::drop_routine(...)

       Removes metadata information of stored routine from the DD
       tables.

    c) template <typename T>
       enum_sp_return_code dd::alter_routine(...)

       Alter metadata information of stored routine in the DD
       tables.

    d) template <typename T>
       enum_sp_return_code dd::find_routine(...)

       Find stored routine in the Data Dictionary table.

B) Following methods are introduced in the sp.cc.

    a) static enum_sp_return_code lock_routine_name(...)

       Acquire MDL lock MDL_EXCLUSIVE or MDL_SHARED on routine name.

    b) static bool show_create_routine_from_dd_routine(...)

       Prepares "SHOW CREATE FUNCTION/PROCEDURE" output using the
       dd::Routine object.

C) Following methods are introduced in the "new" files dd_sp.h & dd.sp.cc

    a) void prepare_sp_chistics_from_dd_routine(...)

       Prepares st_sp_chistics object from the dd::Routine object.

    b) void prepare_return_type_string_from_dd_routine(...)

       Prepares stored routine return type value in string format from
       dd::Routine object.

    c) void prepare_params_string_from_dd_routine(...)

       Prepares stored routine parameters string from the dd::Routine
       object.

    d) bool is_dd_routine_type_functon(...)

       Method to check whether routine is of stored function or not.

Notes:

The WL introduces the following user-visible changes:

  a) The mysql.proc table is now removed. This means that the
     table can no longer be e.g. queried, updated or locked
     explicitly by the user.

  b) A shared metadata lock is now taken when executing
     stored routine. This lock is held until the transaction
     terminates. This means that it will no longer be possible
     to alter or drop a stored routine while it is executing.

  c) As a consequence of removing mysql.proc, ACL on mysql.proc
     no longer applies. For now, full access is only given to
     the definer, any users with global SELECT privilege and
     users with CREATE ROUTINE, ALTER ROUTINE or EXECUTE ROUTINE
     privileges. A more long-term solution for allowing backup
     of stored routines will be implemented in WL#8131/WL#9049.

  d) Before this WL, creating a stored routine having a definition
     containing illegal characters only resulted in a warning.
     With this WL, an error will be raised instead
     (ER_INVALID_CHARACTER_STRING is still used). This makes
     stored routines behave similar to e.g. views.

The stored routine subsystem has been suitably refactored to make use of
new DD table "Routine" and "Parameters" with the new DD APIs provided.

Since mysql.proc does not exists after this WL changes, all MTR tests
which use mysql.proc are either updated to use INFORMATION_SCHEMA's
"Routines" and "Parameters" tables or test cases are removed.