Simplify isEmittedFile check instead of iterating through all source files. Fixes #21459
Simplify isEmittedFile check instead of iterating through all source files.
Fixes #21459

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