patch 8.2.3370: Vim9: no check for white space before type in declaration

Problem:    Vim9: no check for white space before type in declaration.
            (Naohiro Ono)
Solution:   Check for white space like in a compiled function. (closes #8785)

src/testdir/test_vim9_assign.vim

@@ -1722,6 +1722,8 @@ def Test_var_type_check()
   END
   CheckScriptFailure(lines, 'E1069:')
 
+  CheckDefAndScriptFailure(['var n:number = 42'], 'E1069:')
+
   lines =<< trim END
     vim9script
     var name: asdf