D3D11: Use blit SRV format for blits blitSRVFormat stores the format that is used with ANGLE's internal blit shaders. By default, it is the same as the normal SRV format. For integer textures with a red channel, the RTV format is used instead. This makes it possible to change the storage format and the SRV format for the integer textures without affecting the blit format. The blitSRVFormat is used when doing blits in Blit11::copyTexture(). An exception is made for depth/stencil renderbuffer blit - in these cases it is okay to assume that the regular SRV format works for blitting. In the future the regular SRV format for integer textures will be changed to be different from their blit SRV format. TEST=angle_end2end_tests dEQP-GLES3.functional.fbo.blit.* (no regression) dEQP-GLES3.functional.texture.swizzle.* (no regression) BUG=angleproject:1244 Change-Id: Ie0e790e58ec054b64ef5983a09dbfc7754f269ca Reviewed-on: https://chromium-review.googlesource.com/327104 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>