added dt inference to test case

[TEST] Add test linear_past_eltwise_add when the graph has multiple joins where to apply the transformation (was failing in this case) plu test moving linear tensor ops, not only scalar ones

[TEST] Add test to verify that CollapseRepeatedOp only operates on linear segments. Add check to previous test to verify that the transformation is doing the required job

[TEST] Add test linear move_add_past_mul for non_linear graphs and improve previous test by checking if doing job

thanks to @quetric for pointing this out