Fix some ftdetect issues from tests

ftplugin/groovy.vim

@@ -0,0 +1,23 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'groovy') == -1
+
+" Vim filetype plugin file
+" Language:	groovy
+" Maintainer:	Justin M. Keyes <justinkz@gmail.com>
+" Last Change:	2016 May 22
+
+if exists('b:did_ftplugin')
+  finish
+endif
+let b:did_ftplugin = 1
+
+let s:cpo_save = &cpo
+set cpo-=C
+
+let b:undo_ftplugin = 'setlocal commentstring<'
+
+setlocal commentstring=//%s
+
+let &cpo = s:cpo_save
+unlet s:cpo_save
+
+endif