Remove closeStream method from fs

Author: rosen-vladimirov

test/stubs.ts

@@ -140,10 +140,6 @@ export class FileSystemStub implements IFileSystem {
 
 	symlink(sourcePath: string, destinationPath: string): void { }
 
-	closeStream(stream: any): IFuture<void> {
-		return undefined;
-	}
-
 	setCurrentUserAsOwner(path: string, owner: string): IFuture<void> {
 		return undefined;
 	}