Drop jerry_port_putchar

Recent changes eliminate the need for `jerry_port_putchar`. As port
API discussions don't make it likely that it will ever be needed
again, this patch removes its declaration from jerry-port.h and its
implementations from the port(s).

The related code in jerry-libc is not needed either: whatever `putc`
(and `puts`) can do, `printf` can do as well.

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

jerry-core/jerry-port.h

@@ -34,7 +34,6 @@ extern "C"
  */
 int jerry_port_logmsg (FILE *stream, const char *format, ...);
 int jerry_port_errormsg (const char *format, ...);
-int jerry_port_putchar (int c);
 
 /*
  * Termination Port API