[SYCL] DPC++ support runtime compilation?

**Is your feature request related to a problem? Please describe**
I'm trying to add SYCL backend to TVM. In it, kernel source code is automatically generated at runtime, so source code needs to be compiled at runtime.

**Describe the solution you would like**
Runtime compilation similar to nvrtc.

**Describe alternatives you have considered**
I'm know this is a little tricky in SYCL, because SYCL is based on a single-source model. The alternative I'm taking now is to write the generated source code to a file and compile the file to a dynamic link library. This alternative is somewhat heavy.
Any suggestions?