Apply JIT-LTO to CAGRA search kernels

[divyegala]

JIT compiling CAGRA search kernels is going to be pretty challenging. Currently, at least the single-cta search kernels use:

1. some kind of function-pointer indirection to load data and compute distance
2. the device functions for these are allocated in memory by launching a separate kernel
3. this doesn’t work in JIT-LTO because each kernel we compile is its own module, meaning we can’t share device function pointer addresses
4. we will need to reverse almost all of CAGRA - separable compilation for distance computation #296