Add a testcase for ubsan

Dockerfile.dev

@@ -100,6 +100,9 @@ RUN cd test && \
         for test in stacksmash; do \
             $arch-w64-mingw32-clang $test.c -o $arch/$test-asan.exe -fsanitize=address -g -gcodeview -Wl,-pdb,$arch/$test-asan.pdb || exit 1; \
         done; \
+        for test in ubsan; do \
+            $arch-w64-mingw32-clang $test.c -o $arch/$test.exe -fsanitize=undefined || exit 1; \
+        done; \
     done
 
 # Build libssp