Fix CMake for adding GTest/

thirdparty/GTest/CMakeLists.txt

-set(KWSYS_NAMESPACE adios2sys)
-set(KWSYS_USE_DynamicLoader ON)
-set(KWSYS_BUILD_SHARED OFF)
-if(NOT ADIOS_BUILD_SHARED_LIBS)
-  set(KWSYS_INSTALL_EXPORT_NAME adios2)
-  set(KWSYS_INSTALL_LIB_DIR ${CMAKE_INSTALL_LIBDIR})
-endif()
+set(BUILD_GTEST ON)
+set(BUILD_GMOCK OFF)
 
-add_subdirectory(adios2sys)
-
-# Add the include usage requirements for KWSys
-target_include_directories(adios2sys
-  INTERFACE ${CMAKE_CURRENT_BINARY_DIR}/adios2sys
-)
+add_subdirectory(googletest)