patch 8.1.0967: stray dependency in test Makefile

Problem:    Stray dependency in test Makefile.
Solution:   Remove it. (Masato Nishihata, closes #4018)
diff --git a/src/testdir/Makefile b/src/testdir/Makefile
index c3ba8ab..45c520d 100644
--- a/src/testdir/Makefile
+++ b/src/testdir/Makefile
@@ -148,7 +148,7 @@
 newtestssilent: $(NEW_TESTS_RES)
 
 
-.vim.res: writevimcmd
+.vim.res:
 	@echo "$(VIMPROG)" > vimcmd
 	@echo "$(RUN_VIMTEST)" >> vimcmd
 	$(RUN_VIMTEST) $(NO_INITS) -S runtest.vim $*.vim $(REDIR_TEST_TO_NULL)