This patch fixes 2 format issues in the intermediate output of
structs and interface blocks in indexing expressions.
1. Adds the missing line feed (LF) so that the next expression can
be started in a newline correctly.
2. Remove unnecessary mDepth++ and mDepth-- to avoid redundant
indentions.

BUG=angleproject:2031

Change-Id: I04e36443a851df4c26ba6b1cbf3a7f8fd6405d3a
Reviewed-on: https://chromium-review.googlesource.com/499569Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>