Remove the built-in print and the jerry_port_console port API functions (#1749)

The built-in `print` is removed from jerry-core, but an external
`print` implementation is added to jerry-main. From now on, all
embedders of the engine have to implement their own `print` if they
need such a functionality.

For printing results in REPL mode of jerry-main, the external
`print` handler is called directly instead of looking up the `print`
function registered into the global object. (The two are the same,
but the indirection is not needed anymore.)

Because jerry-core does not contain `print` anymore,
`jerry_port_console` is removed from the port API. The default port
is updated, i.e., the implementation of `jerry_port_console` is
removed. Additionally, all references to `jerry_port_console` in
jerry-main are replaced by `printf`.

Speculatively, `jerry_port_console` is also removed from all
non-default targets. Most targets implemented it for the sake of the
engine only; in those targets the removal was trivial. Where the
function was called from the embedder application as well, the
calls were replaced with equivalents (e.g., `printf`, `printk`).

NOTE 1: This is a breaking change!

NOTE 2: This patch still leaves several targets without a JS `print`
implementation.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

targets/mbed/source/port/jerry_port.c

@@ -22,19 +22,6 @@
 
 #include "mbed-hal/us_ticker_api.h"
 
-/**
- * Provide console message implementation for the engine.
- */
-void
-jerry_port_console (const char *format, /**< format string */
-                    ...) /**< parameters */
-{
-  va_list args;
-  va_start (args, format);
-  vfprintf (stdout, format, args);
-  va_end (args);
-} /* jerry_port_console */
-
 /**
  * Provide log message implementation for the engine.
  */
@@ -62,7 +49,7 @@ jerry_port_fatal (jerry_fatal_code_t code) /**< fatal code enum item */
 
 /**
  * Implementation of jerry_port_get_time_zone.
- * 
+ *
  * @return true - if success
  */
 bool