Improve regexp that matches functional tests

The regexp was added by @semanticart in https://github.com/colszowka/simplecov/commit/a7024ef12b7c1fe362918267f4ed1d1e66cc14f5.

This patch improves the regular expression in two ways:

1. It adds escape characters (`/`) before the curly braces (`{`, `}`).
2. It removes unnecessary question marks (`?`).

In regular expressions, curly braces are meta-characters used to specify the amount of repetition, so they need to be escaped. The Ruby regular expression engine is smart enough to figure out what to do in this case, but it outputs the following warnings on that line:

    warning: regexp has invalid interval
    warning: regexp has `}' without escape

The question marks are not necessary because dot star (`.*`) matches zero or more of any character.

I’ve also taken this opportunity to clean up whitespace, which is one of my pet peeves. I’ve done so in a separate commit, so feel free to `git cherry-pick` if, for whatever reason, you prefer the whitespace the way it is.