D3D11: Serialize and deserialze mImage2DUniforms. mImage2DUniforms was not saved with the program binary causing shaders with images to fail compilation when loaded from binary. BUG: angleproject:4519 BUG: b:152292873 Change-Id: I51581031ae1f9d4b4d986057ef3f876d809c7f24 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2124587 Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com> Commit-Queue: Courtney Goeltzenleuchter <courtneygo@google.com>