patch 8.2.5026: Vim9: a few lines not covered by tests

Problem:    Vim9: a few lines not covered by tests.
Solution:   Delete dead code.  Add a few test cases. make "12->func()" work.

src/ex_docmd.c

@@ -3506,6 +3506,18 @@ one_letter_cmd(char_u *p, cmdidx_T *idx)
     return FALSE;
 }
 
+/*
+ * Return TRUE if "cmd" starts with "123->", a number followed by a method
+ * call.
+ */
+    int
+number_method(char_u *cmd)
+{
+    char_u *p = skipdigits(cmd);
+
+    return p > cmd && (p = skipwhite(p))[0] == '-' && p[1] == '>';
+}
+
 /*
  * Find an Ex command by its name, either built-in or user.
  * Start of the name can be found at eap->cmd.
@@ -3716,6 +3728,13 @@ find_ex_command(
 	    }
 	}
 
+	// 1234->func() is a method call
+	if (number_method(eap->cmd))
+	{
+	    eap->cmdidx = CMD_eval;
+	    return eap->cmd;
+	}
+
 	// "g:", "s:" and "l:" are always assumed to be a variable, thus start
 	// an expression.  A global/substitute/list command needs to use a
 	// longer name.