Remove references to compile/build_with_source

[Pennycook]

These functions were removed alongside the program object in SYCL 2020.

The section correctly pointed to kernel_bundle as the replacement, but referred to member functions that didn't exist.

Closes #389.

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I'm honestly not sure whether I've fixed this correctly, and I was surprised to discover that we define both a make_kernel_bundle and a create_bundle function. I think this is correct, though -- a developer can create a cl_program from source using OpenCL functionality, and then create a kernel_bundle from that.

[gmlueck]

I was surprised to discover that we define both a make_kernel_bundle and a create_bundle function

This occurs because the signature of make_kernel_bundle has to have a specific set of parameters that are dictated by the backend_traits. See section 4.5.1.3. Personally, I'd like to remove all these make_ functions from the core spec and let each backend define its own set of functions that construct SYCL objects from backend objects.

[Pennycook]

This occurs because the signature of make_kernel_bundle has to have a specific set of parameters that are dictated by the backend_traits. See section 4.5.1.3. Personally, I'd like to remove all these make_ functions from the core spec and let each backend define its own set of functions that construct SYCL objects from backend objects.

I agree. Trying to force all of the backend interoperability functions to use the same interface is just going to make lots of work for the WG and implementers: either the interface has to keep being updated to chase the latest implementation requirements, or implementers have to constrain features and capabilities in order to satisfy interoperability.

@tomdeakin, could we make time in the SYCL WG agenda to discuss potentially deprecating all of these make_ functions?