Extend renderpass tests to use input attachments

Extend renderpass tests to use input attachments

- Render only values 0 and 1 to all attachments.
- The value depends on attachment, subpass and pixel location.
- Depth formats also sets gl_FragDepth to 0.0 or 1.0 depending on location.
- Stencil uses only values 0 and 0xff.
- Verification requires that the quads are rasterized exactly and
  that all result values are either 0 or 1.
- Input attachment containing 1s and 0s are interpreted as true and
  false bools and input values are combined with boolean operations and
  written to shader outputs.

See #447
Change-Id: I4ebe3d9b5151d40558e473a028ee458cf6285a85