Instead of using an egl::Error return value, errors are recorded
on the egl::Thread immediately at the call site. This makes the
code work the same way as in the GL entry points.

Updates the EGL "try" macros to include a special handler for the
EGL validation entry points. Uses a special ValidationContext
helper class to preserve the existing info.

Bug: angleproject:5378
Change-Id: I897f221a41fe406676950600e4ac559081b9f541
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2551790
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Tim Van Patten <timvp@google.com>