IDN display: Block U+0307 after i or U+0131

U+0307 (dot above) after i, j, l, or U+0131 (dotless i) would be
very hard to see if possible at all. This is not blocked
by the 'repeated diacritic' check because i is not decomposed
into dotless-i + U+0307. So, it has to be blocked separately.

Also, change the indentation in the output of
idn_test_case_generator.py .

This change blocks 80+ domains out of a million IDNs in .com TLD.

BUG=750239
TEST=components_unittests --gtest_filter=*IDN*

Change-Id: I4950aeb7aa080f92e38a2b5dea46ef4e5c25b65b
Reviewed-on: https://chromium-review.googlesource.com/607907
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Matt Giuca <mgiuca@chromium.org>
Commit-Queue: Jungshik Shin <jshin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#502987}