Autogen: Use output caching GetExecutableTestOutput

Use the output caching cmQtAutoGenGlobalInitializer::GetExecutableTestOutput
method to avoid identical calls to moc, uic and rcc.

Closes #18947
10 jobs for autogen_cache_binary_checks
Status Job ID Name Coverage
  External
passed ghostflow-check-master

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager

passed ghostflow-stager