- Remove variable name prefix from Info structs to be more consistent
  with other ANGLE structs.
- Fix CL object validation check with magics, since the Mesa solution
  doesn't work without RTTI.
- Add support for some extensions required by OpenCL 1.1 and for some
  optional extensions.
- Fix more conformance bugs.

Bug: angleproject:6015
Change-Id: I41b1c45d95059a9994f5dc78bf9b74476cc6f2d4
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2956349
Commit-Queue: John Plate <jplate@google.com>
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>