Include CheckCXXSymbolExists when FLATBUFFERS_LOCALE_INDEPENDENT=0
When using the Arm NN Tensorflow Delegate or Arm NN TfLite parser an abort is caused by the destruction of flatbuffers::ClassicLocale::~ClassicLocale() before the Arm NN ExecuteNetwork process exits. 

Setting FLATBUFFERS_LOCALE_INDEPENDENT=0 allows ClassicLocale to be compiled out. however it requires CheckCXXSymbolExists to be included.