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_expand_dllpath.vim b/src/testdir/test_expand_dllpath.vim
index 1542095..76bd787 100644
--- a/src/testdir/test_expand_dllpath.vim
+++ b/src/testdir/test_expand_dllpath.vim
@@ -1,3 +1,5 @@
+" Test for expanding dllpath options
+
 func s:test_expand_dllpath(optname)
   let $TEST_EXPAND_DLLPATH = '/dllpath/lib' . substitute(a:optname, '\zedll$', '.', '')
   execute 'let dllpath_save = &' . a:optname
@@ -30,3 +32,5 @@
 call s:generate_test_if_exists('pythonthreedll')
 call s:generate_test_if_exists('rubydll')
 call s:generate_test_if_exists('tcldll')
+
+" vim: shiftwidth=2 sts=2 expandtab