webrev: sdiff view indentation does not account for width line number

The sdiff view of webrev seems to not account for the width of the line numbers. With every additional digit, the code is shifted an additional character to the right.

This can be seen in the attached sdiff file (from the JDK-8183372, fwiw), at the transition from lines 9->10 and 99->100.

When reviewing code, this looks like a phantom indentation problem in the code change.