Map U+0454 (є) to 'e' (small E)

Bug: 803571
Test: components_unittests --gtest_filter=*IDN*
Change-Id: I8cc473d0e74208076a2aa17c1869d14bbfaa20ed
Reviewed-on: https://chromium-review.googlesource.com/882006
Commit-Queue: Jungshik Shin <jshin@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#531739}