Disable libc++ benchmarks with sanitizers

According to llvm/llvm-project#115361 (comment)

Author: vitalybuka

zorg/buildbot/builders/sanitizers/buildbot_functions.sh

@@ -288,6 +288,7 @@ function build_stage2 {
       -DLLVM_ENABLE_RUNTIMES='libcxx;libcxxabi;libunwind' \
       -DLIBCXX_TEST_PARAMS='long_tests=False' \
       -DLIBCXXABI_USE_LLVM_UNWINDER=OFF \
+      -DLIBCXX_INCLUDE_BENCHMARKS=OFF \
       -DLLVM_USE_SANITIZER=${llvm_use_sanitizer} \
       -DCMAKE_C_FLAGS="${fsanitize_flag} ${cmake_libcxx_cflags} ${fno_sanitize_flag}" \
       -DCMAKE_CXX_FLAGS="${fsanitize_flag} ${cmake_libcxx_cflags} ${fno_sanitize_flag}" \