ci(tool): Add stages for roundtrip tests

This commit introduces two new stages for enhanced testing of the translator and LLVM dependency. Specifically the roundtrip tests consist of deserializing a provided TOSA flatbuffer then serializing it back to flatbuffer and checking for equivalency. CTS tests are generated to ensure good coverage of these tests.

Co-authored-by: Ian Tayler Lessa ian.taylerlessa@arm.com Co-authored-by: Jeremy Johnson jeremy.johnson@arm.com Signed-off-by: Luke Hutton luke.hutton@arm.com