Add GetFilteredRegisteredKernels and refactor

GetFilteredRegisteredKernels makes it easier for users to query at runtime which kernels are available which match some predicate. The most common usage will be querying which kernels are available for a given op, so we add the specialized GetRegisteredKernelsForOp.

This is part of the work to make available kernels possible to query, to support Swift For TensorFlow. There are also a number of github issues asking for the functionality.

I will add C API and Python API support in upcoming changes.

PiperOrigin-RevId: 205656251