File viewer doesn't display newline(s) at start of file. (BB-7280)

When you have a file starting with empty lines the
web sourcebrowser doesn't display them - it shows
the first non-empty line as line 1, which makes all
the line numbers in that file wrong.

The raw view shows the newlines correctly.

I don't know if it's relevant, but this occured in an .sql
file.