Each invocation of `xcodebuild -version` can take > 100ms. Caching the result reduces startup time of UnrealBuildTool and AutomationTool by 1-2 seconds.
#jira none
#ROBOMERGE-SOURCE: CL 16999582 in //UE5/Main/...
#ROBOMERGE-BOT: STARSHIP (Main -> Release-Engine-Test) (v838-16927207)
[CL 16999589 by jonathan adamczewski in ue5-release-engine-test branch]