Vulkan: Expose an unimplemented EGL_ANGLE_robust_resource_initialization. Simply exposing the extension string allows the passthrough command decoder to initialize for testing. It still fails all tests that use the extension. BUG=angleproject:2722 Change-Id: I71f408d05009afb594835c0b741256e26209d93e Reviewed-on: https://chromium-review.googlesource.com/1138824 Commit-Queue: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>