Changes the interval boundaries to exclude the first delimiter
that encloses a region.
Change-Id: Ia9186e584d9038b4220cad11d418fa9881e51e8d
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/60346
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Alastair Donaldson <afdx@google.com>
Commit-Queue: Alastair Donaldson <afdx@google.com>
egj