The "file" variable in a LineEntry was mapped using target.source-map, except when stepping through inlined code. This patch adds a new variable to LineEntry, "original_file", that contains the original file from the debug info. "file" will continue to (possibly) be mapped.
Some code has been changed to use "original_file". This is code dealing with symbols. Code dealing with source files will still use "file". Reviewers, please confirm that these particular changes are correct.
Tests run on Ubuntu 12.04 show no regression.
In this case, we probably want to try both. This code is where we set file & line breakpoints. If we're showing the re-mapped file in source listings or anything like that, we should allow people to use it to set breakpoints. But I wouldn't want setting breakpoints by the debug info name to fail as well.