…ionExecutorCache instances are consistently named executor_cache.

…idevice/executor.[cpp,h] and rename to HostIrExecutor.

…dispatch

…cutor through ExecutorDispatch.

…dispatch

…dispatch

During deserialization, iterate over all executors in `FusionKernelRuntime`. If it is a `KernelExecutor`, use the `group_id` for the `SegmentedGroup` to find the corresponding serialized `KernelExecutors` buffer. Then, use the buffer to deserialize the `KernelExecutor`. For `HostIrExecutor` and `ExprEvalExecutor` compile normally.

…r user scheduling. (#3357)

The goal is to set `fusion_id` and `device_id` when creating
`KernelExecutor` for `UserSchedule. Previously, it was set during
`FusionExecutor::compileFusion`. This PR is stacked on
`executor_dispatch`

**Changes to `UserSchedule` cache system:**
**Current:** The map key is the integer value of input arguments. The
vector is of size `device id`.
`std::unordered_map<size_t, std::vector<UserSchedule>>
user_def_schedules;`

**New:** The key to first map is the integer value of input arguments.
The key to second map is of `device`.

**Why?** We can set the the `fusion_id` and `device_id` in the
constructor of `UserSchedule` and `KernelExecutor`.