Test Runner: Add stub register function to GLES 1 CTS. These tests use the same main function as end2end_tests. Add the register function stub so the compilation works correctly in standalone and component builds. Bug: angleproject:4449 Change-Id: Id240a834ae0e358d0e2520b12842f3f337c0aa31 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2081514 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>