citest/sim01: disable sim:libcxxtest on macOS

There have been errors like below on macOS for sim:libcxxtest

```
Error: /Applications/Xcode.../include/mach/vm_page_size.h:59:44:
error: expected ';' after top level declarator
```
This patch tries to disable that check on macOS.

Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>

tools/ci/testlist/sim-01.dat

@@ -36,6 +36,9 @@
 # macOS matter compilation is not currently supported
 -Darwin,sim:matter
 
+# macOS has trouble with sim:libcxxtest
+-Darwin,sim:libcxxtest
+
 # Boards build by CMake
 CMake,sim:alsa
 CMake,sim:bluetooth