patch 8.0.0890: still many old style tests

Problem:    Still many old style tests.
Solution:   Convert several tests to new style. (Yegappan Lakshmanan)
diff --git a/src/Makefile b/src/Makefile
index ca8b1a3..de4b240 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2169,6 +2169,7 @@
 	test_functions \
 	test_ga \
 	test_getcwd \
+	test_getvar \
 	test_gf \
 	test_glob2regpat \
 	test_global \
@@ -2180,6 +2181,7 @@
 	test_help \
 	test_help_tagjump \
 	test_hide \
+	test_highlight \
 	test_history \
 	test_hlsearch \
 	test_increment \