Add support for the EGL_EXT_image_dma_buf_import on EGL implementations
that support it natively. This extensin is used on ozone to import
native compositing buffers.

This patch also adds new tokens in EGL_EXT_image_dma_buf_import_modifiers
which are used in eglCreateImageKHR.

BUG=angleproject:4529

Change-Id: I49bff831b591fb19fcdcec1145c7a61f5d8020c4
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2128190
Commit-Queue: Jiajia Qin <jiajia.qin@intel.com>
Reviewed-by: Jonah Ryan-Davis <jonahr@google.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>