Don't reposition the input stream when a \r is immediately followed by
the end of input.
Without that change, the unit test testMacLines would cause an endless
loop for JDK 1.1, at least with:
$ java -fullversion
java full version "Linux_JDK_1.1.8_v3_green_threads"
git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@270995 13f79535-47bb-0310-9956-ffa450edef68