patch 8.2.1432: various inconsistencies in test files

Problem:    Various inconsistencies in test files.
Solution:   Add modelines where they were missing.  Use Check commands instead
            of silently skipping over tests.  Adjust indents and comments.
            (Ken Takata, closes #6695)
diff --git a/src/testdir/test_jumplist.vim b/src/testdir/test_jumplist.vim
index 9cfbbe2..57a5100 100644
--- a/src/testdir/test_jumplist.vim
+++ b/src/testdir/test_jumplist.vim
@@ -1,10 +1,10 @@
 " Tests for the jumplist functionality
 
+source check.vim
+
 " Tests for the getjumplist() function
 func Test_getjumplist()
-  if !has("jumplist")
-    return
-  endif
+  CheckFeature jumplist
 
   %bwipe
   clearjumps
@@ -64,3 +64,5 @@
 
   call delete("Xtest")
 endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab