Apply Upstream Commit: windowscodecs: BitmapScaler_CopyPixels: Do not demand a larger buffer than necessary.

[gamingdoom]

This commit contains a bugfix related to bitmap scaling. It fixes the CopyPixels function rejecting parameters that are valid on windows, where the destination bitmap buffer doesn't include padding for the last scanline. This behavior is relied upon by DirectXTex's mipmap generation.

This commit fixes the black texture problem in BeamNG.drive reported in ValveSoftware/Proton#1237

This commit has just been merged into proton experimental bleeding-edge (here).