Change tests to use normal spice kernel management

[rfrenchseti]

Currently the various oops and oops hosts tests load their own kernels, either directly from the normal SPICE kernel directory, or directly from a special SPICE kernel directory associated with the test files. Both of these are problematic because it bypasses the normal kernel management currently in spicedb and eventually in spyceman. Remove all references to cspyce.furnsh() from the oops source code and tests, and replace with appropriate calls to the kernel management system.