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/common/freertos/freertos_malloc.c

@@ -20,3 +20,9 @@ os_realloc(void *ptr, unsigned size)
 void
 os_free(void *ptr)
 {}
+
+int
+os_dumps_proc_mem_info(char *out, unsigned int size)
+{
+    return -1;
+}