Refine test checks, clean up the output directory

Author: MaxDesiatov

test/Documentation/docc.swift

@@ -1,6 +1,6 @@
 // REQUIRES: OS=macosx
 
-// RUN: mkdir $(dirname %t)/out
-// RUN: xcrun docc convert --output-path $(dirname %t)/out --ide-console-output --allow-arbitrary-catalog-directories $(dirname %utils)/docs
-// RUN: test $(du -c $(dirname %t)/out | tail -1 | awk '{ print $1 }') -gt 18000 && echo success
+// RUN: %empty-directory(%t)
+// RUN: xcrun docc convert --output-path %t --ide-console-output --allow-arbitrary-catalog-directories $(dirname %utils)/docs
+// RUN: test $(du -c %t | tail -1 | awk '{ print $1 }') -gt 1000 && echo success
 // CHECK: success