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/linux-sgx/sgx_platform.c

@@ -51,6 +51,12 @@ os_free(void *ptr)
     free(ptr);
 }
 
+int
+os_dumps_proc_mem_info(char *out, unsigned int size)
+{
+    return -1;
+}
+
 int
 putchar(int c)
 {