Add approprite formatting function for gtests.

[CAHEK7]

Some of the tests like layernorm (https://github.com/ROCm/MIOpen/blob/97ec5080860fd432b37e426bd3726cf6c8634b7a/test/gtest/addlayernorm.hpp#L102) have a special operator<< for human readable tests case formatting.

A lot of the other cases do not have it and it should be added everywhere.

[atamazov]

@CAHEK7 If the test case can be unambiguously described by the problem under the test, then we can re-use the serialization function, which should exist in each problem class. What do you think?

[CAHEK7]

@atamazov it will be generalized if the tests are using the same structure for the test cases or the structures are different, but compatible and can be printed via template function.