[SYCL][CI] all target does not seem to be tested.

[coldav]

Describe the bug

A recent commit broke the all target (fixed in #18647) for building dpc++. This didn't seem to be tested by PR testing or post commit testing. I appreciate the default compile.py target is deploy-sycl-toolchain, but I would expect the all target to still work and therefore be tested.

Can we have clarity on whether the all target is expected to work and if so could we ensure it is tested? If not can we look at erroring out early?

To reproduce

1. Include a code snippet that is as short as possible
2. Specify the command which should be used to compile the program
3. Specify the command which should be used to launch the program
4. Indicate what is wrong and what was expected

Environment

• OS: [e.g Windows/Linux]
• Target device and vendor: [e.g. Intel GPU]
• DPC++ version: [e.g. commit hash or output of clang++ --version]
• Dependencies version: [e.g. the output of sycl-ls --verbose]

Additional context

No response

[sarnex]

I'll try to add this to the nightly.