GitLab

Changing LEX_CSTRING* parameters of LEX::make_sp_name() to Lex_ident_sys_st.

This makes the code clear because a value of Lex_ident_sys_st has
some guaranteed additional constraints over a base LEX_CSTRING:

- Its LEX_CSTRING::str is not NULL (sql_yacc.yy would abort otherwise)
- Its LEX_CSTRING::str is 0-terminated
- Its a valid utf8 string
- The string pointed by LEX_CSTRING::str was created on THD::mem_root

Also changing "pass by pointer" to "pass by reference",
as these parameters can never be NULL - they are Bison stack variables.