Specify WORKING_DIRECTORY to execute_process() in GoogleTestAddTests

Modules/GoogleTestAddTests.cmake

@@ -30,6 +30,7 @@ if(NOT EXISTS "${TEST_EXECUTABLE}")
 endif()
 execute_process(
   COMMAND ${TEST_EXECUTOR} "${TEST_EXECUTABLE}" --gtest_list_tests
+  WORKING_DIRECTORY "${TEST_WORKING_DIR}"
   TIMEOUT ${TEST_DISCOVERY_TIMEOUT}
   OUTPUT_VARIABLE output
   RESULT_VARIABLE result