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_getcwd.vim b/src/testdir/test_getcwd.vim
index 78f9df6..2d78949 100644
--- a/src/testdir/test_getcwd.vim
+++ b/src/testdir/test_getcwd.vim
@@ -1,3 +1,5 @@
+" Test for getcwd()
+
 func GetCwdInfo(win, tab)
   let tab_changed = 0
   let mod = ":t"
@@ -262,3 +264,5 @@
   enew | only | tabonly
   new
 endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab