lib/unicode_normalize/tables.rb: remove auto generated file.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48074 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
common.mk: UNICODE_FILES

* common.mk (UNICODE_FILES): revert the rule that Unicode data
  files depend on downloader target, and add missing dependency of
  lib/unicode_normalize/tables.rb

* common.mk (after-configure): removed as srcdir should be
  read-only after update.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48075 b2dd03c8-39d4-4d8f-98ff-823fe69b080e