Use fs.existsSync to check for cancellation (#36190)
Use fs.existsSync to check for cancellation (#36190)

Unlike statSync, it doesn't throw if the file doesn't exist, saving both
time and allocations.
alexeagle/TypeScript,Microsoft/TypeScript,weswigham/TypeScript,microsoft/TypeScript,nojvek/TypeScript,SaschaNaz/TypeScript,SaschaNaz/TypeScript,RyanCavanaugh/TypeScript,kitsonk/TypeScript,weswigham/TypeScript,RyanCavanaugh/TypeScript,minestarks/TypeScript,kpreisser/TypeScript,Microsoft/TypeScript,minestarks/TypeScript,microsoft/TypeScript,minestarks/TypeScript,weswigham/TypeScript,kpreisser/TypeScript,alexeagle/TypeScript,kitsonk/TypeScript,kitsonk/TypeScript,Microsoft/TypeScript,nojvek/TypeScript,RyanCavanaugh/TypeScript,alexeagle/TypeScript,kpreisser/TypeScript,nojvek/TypeScript,SaschaNaz/TypeScript,SaschaNaz/TypeScript,microsoft/TypeScript,nojvek/TypeScript