Add bh_print_proc_mem() to dump memory info of current process (#1734)

Only support Posix platforms currently, read memory consumption info from
file "/proc/self/status".

core/shared/platform/rt-thread/rtt_platform.c

@@ -88,6 +88,12 @@ os_free(void *ptr)
     }
 }
 
+int
+os_dumps_proc_mem_info(char *out, unsigned int size)
+{
+    return -1;
+}
+
 static char wamr_vprint_buf[RT_CONSOLEBUF_SIZE * 2];
 
 int