Reduce the usage of strlen

* Improve jerry_string_sz only accept UTF-8 string(that's a rare case accept CESU-8 in c/cpp code)
* The document about jerry_string_sz only support ASCII(the fact is CESU-8 before this MR), update it to support UTF-8 after this MR
* Improve all _sz function to take jerry_value_t that can construct from `jerry_string_sz`
* Improve JERRY_ZSTR_ARG can only accept string literal(that's UTF-8)
* Add function jerry_value_list_free to free a list of jerry_value_t
* All call to jerry_string/jerry_string_cesu8 in core indeed are removed, so when there is no linkage to it, code size is saved

The prototype of new/improved function/macros is:
```c
jerry_value_t jerry_string_cesu8 (const jerry_char_t *buffer_p, jerry_size_t buffer_size);
jerry_value_t jerry_string_utf8 (const jerry_char_t *buffer_p, jerry_size_t buffer_size);
#define jerry_string_sz(str) jerry_string_utf8 (JERRY_ZSTR_ARG (str))

jerry_value_t jerry_error_sz (jerry_error_t error_type, const jerry_value_t message_sz);
jerry_value_t jerry_throw_sz (jerry_error_t error_type, const jerry_value_t message_sz);
jerry_value_t jerry_regexp_sz (const jerry_value_t pattern_sz, uint16_t flags);
jerry_value_t jerry_object_delete_sz (const jerry_value_t object, const jerry_value_t key_sz);
jerry_value_t jerry_object_get_sz (const jerry_value_t object, const jerry_value_t key_sz);
jerry_value_t jerry_object_has_sz (const jerry_value_t object, const jerry_value_t key_sz);
jerry_value_t jerry_object_set_sz (jerry_value_t object, const jerry_value_t key_sz, const jerry_value_t value);
```

Rename jerry_port_log to jerry_port_log_buffer

Add buffer_size parameter for function jerry_port_log_buffer, so that jerry_port_log_buffer
won't need calculate strlen when printing

JerryScript-DCO-1.0-Signed-off-by: Yonggang Luo [email protected]

Author: lygstate

docs/01.CONFIGURATION.md

@@ -155,7 +155,7 @@ Enabling this feature provides detailed error messages where available, like lin
 
 ### Logging
 
-This option can be used to enable log messages during runtime. When enabled the engine will use the `jerry_port_log` port API function to print relevant log messages.
+This option can be used to enable log messages during runtime. When enabled the engine will use the `jerry_port_log_buffer` port API function to print relevant log messages.
 This feature is disabled by default.
 
 | Options |                                              |