patch 8.1.1826: tests use hand coded feature and option checks

Problem:    Tests use hand coded feature and option checks.
Solution:   Use the commands from check.vim in more tests.
diff --git a/src/testdir/test_breakindent.vim b/src/testdir/test_breakindent.vim
index 1dd5aa6..5b8971e 100644
--- a/src/testdir/test_breakindent.vim
+++ b/src/testdir/test_breakindent.vim
@@ -4,9 +4,8 @@
 " while the test is run, the breakindent cacheing gets in its way.
 " It helps to change the tabstop setting and force a redraw (e.g. see
 " Test_breakindent08())
-if !exists('+breakindent')
-  throw 'Skipped: breakindent option not supported'
-endif
+source check.vim
+CheckOption breakindent
 
 source view_util.vim