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

jerry-core/jerryscript-port.h

@@ -68,20 +68,6 @@ void jerry_port_fatal (jerry_fatal_code_t code);
  *  I/O Port API
  */
 
-/**
- * Print a string to the console. The function should implement a printf-like
- * interface, where the first argument specifies a format string on how to
- * stringify the rest of the parameter list.
- *
- * This function is only called with strings coming from the executed ECMAScript
- * wanting to print something as the result of its normal operation.
- *
- * It should be the port that decides what a "console" is.
- *
- * Example: a libc-based port may implement this with vprintf().
- */
-void jerry_port_console (const char *format, ...) __attribute__ ((format (printf, 1, 2)));
-
 /**
  * Jerry log levels. The levels are in severity order
  * where the most serious levels come first.