patch 8.1.2355: test with "man" fails on FreeBSD

Problem:    Test with "man" fails on FreeBSD.
Solution:   Use "-P" instead of "--pager".
diff --git a/src/testdir/test_normal.vim b/src/testdir/test_normal.vim
index c4b38b1..bbb9993 100644
--- a/src/testdir/test_normal.vim
+++ b/src/testdir/test_normal.vim
@@ -1204,8 +1204,8 @@
     return
   endif
 
-  if has('mac')
-    " In MacOS, the option for specifying a pager is different
+  if has('mac') || has('bsd')
+    " In MacOS and BSD, the option for specifying a pager is different
     set keywordprg=man\ -P\ cat
   else
     set keywordprg=man\ --pager=cat