For all "ANGLE Project" copyrights, standardize to the format specified
by the style guide. Changes:
- "Copyright (c)" and "Copyright(c)" changed to just "Copyright".
- Removed the second half of date ranges ("Y1Y1-Y2Y2"->"Y1Y1").
- Fixed a small number of files that had no copyright date using the
  initial commit year from the version control history.
- Fixed one instance of copyright being "The ANGLE Project" rather than
  "The ANGLE Project Authors"

These changes are applied both to the copyright of source file, and
where applicable to copyright statements that are generated by
templates.

BUG=angleproject:3811

Change-Id: I973dd65e4ef9deeba232d5be74c768256a0eb2e5
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1754397
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>