Disable libunwind assertions

Disable libunwind assertions to follow the main branch PR ARM-software#534 and resolve mismatch between libcxxabi and libunwind.

Author: voltur01

CMakeLists.txt

@@ -1224,6 +1224,7 @@ function(
         -DLIBCXX_ENABLE_STATIC=ON
         -DLIBCXX_INCLUDE_BENCHMARKS=OFF
         -DLIBCXX_TEST_PARAMS=executor=${test_executor}
+        -DLIBUNWIND_ENABLE_ASSERTIONS=OFF
         -DLIBUNWIND_ENABLE_SHARED=OFF
         -DLIBUNWIND_ENABLE_STATIC=ON
         -DLIBUNWIND_IS_BAREMETAL=ON