Xcode: Completely disable code signing for compiler id detection

Issue: #17870
8 jobs for 17870-iphone-friendly-cmake
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