drop unnecessary cmake dependency on ext_gtest (#2389)

ngraph_test_util links libgtest, which depends on ext_gtest already.

Co-authored-by: Helmut Grohne <helmut.grohne@intenta.de>

ngraph/test/util/CMakeLists.txt

@@ -36,6 +36,5 @@ if(NGRAPH_LIB_VERSIONING_ENABLE)
 endif()
 target_include_directories(ngraph_test_util PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/.. ${IE_MAIN_SOURCE_DIR}/include)
 target_link_libraries(ngraph_test_util PRIVATE ngraph ngraph_backend libgtest)
-add_dependencies(ngraph_test_util ext_gtest)
 
 install(TARGETS ngraph_test_util DESTINATION ${NGRAPH_INSTALL_LIB})