simplify isFileSystemCaseSensitive test (#17169)
simplify isFileSystemCaseSensitive test (#17169)


TukekeSoft/TypeScript,microsoft/TypeScript,synaptek/TypeScript,Microsoft/TypeScript,minestarks/TypeScript,basarat/TypeScript,nojvek/TypeScript,weswigham/TypeScript,minestarks/TypeScript,basarat/TypeScript,nojvek/TypeScript,minestarks/TypeScript,SaschaNaz/TypeScript,alexeagle/TypeScript,RyanCavanaugh/TypeScript,SaschaNaz/TypeScript,RyanCavanaugh/TypeScript,Eyas/TypeScript,donaldpipowitch/TypeScript,microsoft/TypeScript,kpreisser/TypeScript,SaschaNaz/TypeScript,Microsoft/TypeScript,weswigham/TypeScript,kpreisser/TypeScript,kitsonk/TypeScript,donaldpipowitch/TypeScript,kitsonk/TypeScript,synaptek/TypeScript,nojvek/TypeScript,microsoft/TypeScript,alexeagle/TypeScript,donaldpipowitch/TypeScript,Eyas/TypeScript,synaptek/TypeScript,donaldpipowitch/TypeScript,weswigham/TypeScript,kitsonk/TypeScript,basarat/TypeScript,Microsoft/TypeScript,SaschaNaz/TypeScript,TukekeSoft/TypeScript,kpreisser/TypeScript,TukekeSoft/TypeScript,Eyas/TypeScript,basarat/TypeScript,nojvek/TypeScript,synaptek/TypeScript,alexeagle/TypeScript,Eyas/TypeScript,RyanCavanaugh/TypeScript