MDEV-8766 Wrong result for SELECT..WHERE LENGTH(time_column)=8 AND time_column=TIMESTAMP'2001-01-01 10:20:31'

In some cases NO_ZERO_DATE did not allow datetime values with zero date part
and non-zero time part (e.g. '0000-00-00 10:20:30.123456').
Allowing values of this kind in all known pieces of the code.

fix for ref like "indexed_time = datetime"

added:
  mysql-test/r/temporal_literal.result
  mysql-test/t/temporal_literal.test
modified:
  client/mysqlbinlog.cc
  include/my_time.h
  mysql-test/r/cast.result
  mysql-test/r/partition_innodb.result
  mysql-test/t/cast.test
  mysql-test/t/partition_innodb.test
  sql-common/my_time.c
  sql/field.cc
  sql/item.cc
  sql/item.h
  sql/item_cmpfunc.cc
  sql/item_create.cc
  sql/item_create.h
  sql/item_strfunc.cc
  sql/item_timefunc.cc
  sql/item_timefunc.h
  sql/sql_select.cc
  sql/sql_time.cc
  sql/sql_time.h
  sql/sql_yacc.yy
  storage/spider/spd_db_mysql.cc

This patch:

- Moves all definitions from the mysql_priv.h file into
  header files for the component where the variable is
  defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h

This patch:

- Moves all definitions from the mysql_priv.h file into
  header files for the component where the variable is
  defined
- Creates header files if the component lacks one
- Eliminates all include directives from mysql_priv.h
- Eliminates all circular include cycles
- Rename time.cc to sql_time.cc
- Rename mysql_priv.h to sql_priv.h