Error on empty core.replace for big files
Error on empty core.replace for big files

This never does what the user wants. We already show
a warning before, just in case the user is doing a
replace on a small file (Edge case but possible) but
we shouldn't allow these replaces for big files.

BUG=171030054
PiperOrigin-RevId: 337503235
Change-Id: If9fc4ff89c63cbd7c8c24a296e8ebd144b16b641

google/copybara,google/copybara,google/copybara