The current default is r32g32b32a32 but it requires special support
which is not available on all GPUs, so it is not a very convenient
default.
Instead of changing the default making it different from RTV resoures,
the format is required to always be explicit for UAVs.
The exceptions are counter_buffer and buffers with "stride", which don't
require a format because it is already implied.
This is simply unnecessary and wastes time.
As part of this, simply remove the "all" directive. Only for a couple of tests
is it even potentially interesting to validate all pixels (e.g.
nointerpolation.shader_test), and for those "all" is replaced with an explicit
(0, 0, 640, 480) rect.
In all other cases we just probe (0, 0).
So, if there is an error or a trace on "[pixel shader]" or similar
blocks, they get reported in the line with the tag at the beginning of
the block and no on the line where the next block starts.
