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_scrollbind.vim b/src/testdir/test_scrollbind.vim
index 6c5488b..8074fda 100644
--- a/src/testdir/test_scrollbind.vim
+++ b/src/testdir/test_scrollbind.vim
@@ -1,4 +1,5 @@
 " Test for 'scrollbind' causing an unexpected scroll of one of the windows.
+
 func Test_scrollbind()
   " We don't want the status line to cause problems:
   set laststatus=0
@@ -270,3 +271,5 @@
   new | only!
   set scrollbind& scrollopt& scrolloff& wrap& equalalways& splitbelow&
 endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab