D3D11: Check packPixels memcpy support based on ANGLEFormat Instead of querying DXGI format info to determine whether framebuffer data can be copied to packPixels target memory with memcpy, compare the internal format information from the ANGLE format to the packing format. This makes it possible to change some of the DXGI formats used for integer textures without breaking packPixels. This makes it possible to entirely remove the DXGI format to GL internal format mapping from the DXGI format info table. BUG=angleproject:1244 TEST=angle_end2end_tests, dEQP-GLES3.functional.fbo.* (no regressions), dEQP-GLES3.functional.pbo.* (no regressions), Change-Id: Id5ffd581349e7afe39872d69cb05381f3e78d352 Reviewed-on: https://chromium-review.googlesource.com/329214 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>