Formerly, nonsensical comment ranges would prevent comments from
appearing in diffs. With this change, ranges are normalized by the
ranged comment layer so that they can be translated into valid
annotations.
See also
* Ibcab6e537abe8b81e764b09982a2581ae81463f8 should reject such ranges.
* I019e00063ab5c45c99379f3f9fb74eda0408d63f should avoid this error when
constructing comment emails.
Bug: Issue 5744
Change-Id: Ib5834017f81f81a877b32264ee57d72302911a6c
6a96c8b248