Convert editing/inserting/return-key-with-selection-00[123].html to use w3c test harness
This patch converts "editing/inserting/return-key-with-selection-00[123].html"
to use w3c test harness to simplify test script for improving readability, and
consolidates into "return_key_with_selection.html" since these files use
similar test sample.
BUG=n/a
TEST=n/a; no behavior changes
Committed:
https://crrev.com/8557b5029b080915027dbdf409fb49b2d38bacfe
Cr-Commit-Position: refs/heads/master@{#415265}