Provide transform and inverse method implementations on AbstractBijection

[danielward27]

Provide an implementation for transform and inverse in AbstractBijection, by taking self.transform_and_log_det(x, condition)[0], self.inverse_and_log_det(y, condition)[0] . The original motivation for separately defining the methods was to avoid computing the log_det during transform and inverse. However, under JIT, the code seems to be removed by the compilers dead code elimination, and I have not seen any performance degradation from switching to this simpler approach. There is likely a performance penalty of this approach outside of JIT, but this is not something I am majorly concerned about.

We now only wrap the *_log_det methods with shape checking, as the transform and inverse methods will be checked by calling the *_log_det methods anyway. This does provide some risk for users who have defined custom bijections, as they will now be overwriting the transform and inverse methods, with a non-shape checked version. In general, I'd recommend no longer defining the inverse and transform methods.