Fix for minor typo in bash script

Author: BujSet

.ci/scripts/test_model.sh

@@ -52,7 +52,8 @@ build_cmake_executor_runner() {
   local backend_string_select="${1:-}"
   echo "Building executor_runner"
   rm -rf ${CMAKE_OUTPUT_DIR}
-  if [[ "$backend_string_select" == "XNNPACK"]]; then
+  mkdir ${CMAKE_OUTPUT_DIR}
+  if [[ "$backend_string_select" == "XNNPACK" ]]; then
     echo "Backend $backend_string_select selected"
     cmake -DCMAKE_BUILD_TYPE=Debug \
         -DEXECUTORCH_BUILD_KERNELS_OPTIMIZED=ON \