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_getvar.vim b/src/testdir/test_getvar.vim
index 7ced44d..c82fdd5 100644
--- a/src/testdir/test_getvar.vim
+++ b/src/testdir/test_getvar.vim
@@ -150,3 +150,5 @@
 endfunc
 
 " get({partial}, {what} [, {default}]) - in test_partial.vim
+
+" vim: shiftwidth=2 sts=2 expandtab