Dump compilation options list within a kernel file as a comment

The idea is to have something like:

```
// OPTIONS: -cl-std=CL3.0
__kernel void test0(void) { printf("%-+5d\n", 10); }
```

when, for example, option `--compilation-cache-mode dump-cl-files` or other special option is used. This is needed for maintaining OpenCL-CTS-Kernel-Dumps repo (see discussion [here](https://github.com/KhronosGroup/OpenCL-CTS-Kernel-Dumps/pull/1)).

Start by tracing the `dump-cl-files` compilation-cache mode in OpenCL-CTS and identify where dumped kernel files are assembled. Use the example in the issue and the linked OpenCL-CTS-Kernel-Dumps discussion as the expected format. Done means dumped kernel files include their compilation options as comments while remaining usable kernel source.

Written by the indexing model from the issue text.