message: Remove the use of CMake's GoogleTest module
  Using recent versions of CMake causes `gtest_discover_tests` to fail when parsing `jwt/tink_test_jwt_jwk_set_converter_test`, likely because of the issue in [1].
  Using `add_test` avoids the issue at the price of losing some granularity (from per test case to per test binary).
  [1]
diff: include(CMakeParseArguments)
  -if (NOT ${CMAKE_VERSION} VERSION_LESS 3.9)
  - include(GoogleTest)
  -endif()
  -
  -
  if (TINK_BUILD_TESTS)
  enable_testing()
  endif()
  @@ -210,11 +205,9 @@ function(tink_cc_test)
  set_property(TARGET ${_target_name} PROPERTY CXX_STANDARD ${TINK_CXX_STANDARD})
  set_property(TARGET ${_target_name} PROPERTY CXX_STANDARD_REQUIRED true)
  - if (${CMAKE_VERSION} VERSION_LESS 3.9)
  + # Note: This was preferred over using gtest_discover_tests because of [1].
  + # [1] https://gitlab.kitware.com/cmake/cmake/-/issues/23039
  add_test(NAME ${_target_name} COMMAND ${_target_name} WORKING_DIRECTORY ${CMAKE_BINARY_DIR})
  - else()
  - gtest_discover_tests(${_target_name} WORKING_DIRECTORY ${CMAKE_BINARY_DIR})
  - endif()
  endfunction(tink_cc_test)
  # Declare a C++ Proto library.
  