Bug 1101160. D3D11: Make switch statement better. r=bas

This is the order one would expect.

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extra : rebase_source : 299b3814983d42908c2507028bb1c16c64b0f25f
Bug 1092260. Use PREVENT_INTERNAL_THREADING_OPTIMIZATIONS with D3D11. r=bas

Using this seems to avoid the AMD frame delay bug.

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extra : rebase_source : 1b867ebfef30d1c1a426c7510591770f362d2b28