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_cjk_linebreak.vim b/src/testdir/test_cjk_linebreak.vim
index dfaa8fa..17c5916 100644
--- a/src/testdir/test_cjk_linebreak.vim
+++ b/src/testdir/test_cjk_linebreak.vim
@@ -1,3 +1,5 @@
+" Test for CJK linebreak
+
 scriptencoding utf-8
 
 func Run_cjk_linebreak_after(rigorous)
@@ -95,3 +97,5 @@
     %d_
   endfor
 endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab