[lit] Ensure test output is converted to strings where possible.

 - This cleans up the text output of failing tests when run under PY3.
[lit] Add test coverage of gtest format.
R600/SI: Add pattern for fp_to_uint

This fixes the F2U opcode for the Mesa driver.

Patch by: Marek Olšák

Signed-off-by: Marek Olšák <marek.olsak@amd.com>
R600/SI: Fix an obvious typo

Patch by: Marek Olšák

Signed-off-by: Marek Olšák <marek.olsak@amd.com>
R600/SI: Allow conversion between v32i8 and v8i32

Patch by: Marek Olšák

Signed-off-by: Marek Olšák <marek.olsak@amd.com>
R600/SI: Handle MSAA texture targets

Patch by: Marek Olšák

Signed-off-by: Marek Olšák <marek.olsak@amd.com>
DebugInfo: Prefer references over pointers, pass by const reference for a type that will grow in the future