patch 9.1.1391: Vim does not have a vertical tabpanel

Problem:  Vim does not have a tabpanel
Solution: include the tabpanel feature
          (Naruhiko Nishino, thinca)

closes: #17263

Co-authored-by: thinca <thinca@gmail.com>
Signed-off-by: Naruhiko Nishino <naru123456789@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index 88bf5c3..ef86a7d 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -311,6 +311,7 @@
 	test_tab \
 	test_tabline \
 	test_tabpage \
+	test_tabpanel \
 	test_tagcase \
 	test_tagfunc \
 	test_tagjump \
@@ -567,6 +568,7 @@
 	test_system.res \
 	test_tab.res \
 	test_tabpage.res \
+	test_tabpanel.res \
 	test_tagjump.res \
 	test_taglist.res \
 	test_tcl.res \