D3D11 Texture refactoring: Store ANGLEFormat in TextureStorage11 This is needed to enable removing GetDXGIFormatInfo calls, which are difficult to use correctly due to a texture format being associated with multiple DXGI formats. This is done in preparation of changing some of the DXGI formats associated with integer textures. BUG=angleproject:1244 TEST=angle_end2end_tests, dEQP-GLES3.functional.fbo.* (no regressions) Change-Id: I820b8331e6f9aacfe9979b13118371687c5fca51 Reviewed-on: https://chromium-review.googlesource.com/329075 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>