* Use hipExtLaunchKernelGGL in dispatchlatency sample
* Let it run on NVCC path too
* Refactoring
* Add test_kernel source
* Remove ResultDB
* Remove error checks
- Enable -O3 for hipDispatchLatency.
- Use nearly-null kernel to prevent it from being optimized away.
- Formatting for hipDispatchLatency.
- Formatting for hipInfo.