message: build_system: remove flags for unit tests in windows
  It seems to me that gtest already does something about that
  (not sure how, though), see [1] and [2].
  [1]:
  [2]:
diff: @@ -6,12 +6,6 @@ add_executable(unit_tests_runner
  ${UNIT_TEST_SOURCES}
  )
  -if (MSVC)
  - # We need this to prevent linking errors from happening in the Windows build.
  - target_compile_definitions(unit_tests_runner PRIVATE -DGTEST_LINKED_AS_SHARED_LIBRARY)
  - target_compile_options(unit_tests_runner PUBLIC "/wd4251" "/wd4275")
  -endif()
  -
  target_compile_definitions(unit_tests_runner PRIVATE FAKE_TIME=1)
  set_target_properties(unit_tests_runner
  