Revert "repl: disable Ctrl+C support on win32 for now"

This reverts commit f59b8888
now that the libuv update containing the proper fix has
landed in 63243bcb.

Ref: https://github.com/libuv/libuv/pull/1054
Ref: https://github.com/nodejs/node/issues/7837
PR-URL: https://github.com/nodejs/node/pull/8645


Reviewed-By: Nikolai Vavilov <vvnicholas@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>