tests/complete: don't remove $PWD

This test removes $PWD which would cause an error if it were to start
a new process.  Normaly we would "cd -" before the removal but later
assertions expect an empty $PWD, so stay there, but don't remove it
to prevent possible surprise.

tests/checks/complete.fish

@@ -541,7 +541,7 @@ begin
     # CHECK: Empty completions
 end
 
-rm -$f $tmpdir/*
+rm $tmpdir/*
 
 # Leading dots are not completed for default file completion,
 # but may be for custom command (e.g. git add).
@@ -557,8 +557,6 @@ echo "Should be nothing"
 complete -C'dotty '
 # CHECK: .abc
 
-rm -r $tmpdir
-
 complete -C'complete --command=mktemp' | string replace -rf '=mktemp\t.*' '=mktemp'
 # (one "--command=" is okay, we used to get "--command=--command="
 # CHECK: --command=mktemp