patch 8.2.1449: some test makefiles delete files that are not generated

Problem:    Some test makefiles delete files that are not generated.
Solution:   Remove the deletion commands.
diff --git a/src/testdir/Make_amiga.mak b/src/testdir/Make_amiga.mak
index 1e8df19..843ea1e 100644
--- a/src/testdir/Make_amiga.mak
+++ b/src/testdir/Make_amiga.mak
@@ -17,7 +17,7 @@
 	csh -c echo ALL DONE
 
 clean:
-	csh -c \rm -rf *.out Xdir1 Xfind XfakeHOME Xdotest small.vim tiny.vim mbyte.vim test.ok viminfo
+	csh -c \rm -rf *.out Xdir1 Xfind XfakeHOME Xdotest test.ok viminfo
 
 .in.out:
 	copy $*.ok test.ok