patch 9.0.1529: code style test doesn't check for space after "if"

Problem:    Code style test doesn't check for space after "if".
Solution:   Add a test for space.
diff --git a/src/testdir/test_codestyle.vim b/src/testdir/test_codestyle.vim
index ec476c0..3553063 100644
--- a/src/testdir/test_codestyle.vim
+++ b/src/testdir/test_codestyle.vim
@@ -36,6 +36,10 @@
     cursor(1, 1)
     lnum = search('else\s*{', '', 0, 0, skip)
     assert_equal(0, lnum, fname .. ': curly after "else"')
+
+    cursor(1, 1)
+    lnum = search('\<\(if\|while\|for\)(', '', 0, 0, skip)
+    assert_equal(0, lnum, fname .. ': missing white space after "if"/"while"/"for"')
   endfor
 
   bwipe!