test: fix test-debugger-repl-break-in-module

The line number checks in test-debugger-repl-break-in-module were
checking for line numbers that exceed the total number of lines in the
files that were being inspected. Change the checks to match the actual
files.

PR-URL: https://github.com/nodejs/node/pull/6686


Reviewed-By: Ben Noorhduis <info@bnoordhuis.nl>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>