patch 8.0.0401: test fails with missing balloon feature

Problem:    Test fails with missing balloon feature.
Solution:   Add check for balloon feature.
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index eeeb4e3..cd58f63 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -468,6 +468,8 @@
 endfunc
 
 func Test_balloon_show()
-  " This won't do anything but must not crash either.
-  call balloon_show('hi!')
+  if has('balloon_eval')
+    " This won't do anything but must not crash either.
+    call balloon_show('hi!')
+  endif
 endfunc
diff --git a/src/version.c b/src/version.c
index fd4cdb1..932132d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    401,
+/**/
     400,
 /**/
     399,