DPC++ daily 2022-11-02

[SYCL] Improve mock PI plugin (#7198)

The patch adds more logic to default redefinitions of PI APIs:

    1. Allocate, refcount and deallocate various handles
    2. Handle sub-buffer creation

Also the patch adds support for adding PI functions to be
called in addition (before or after) to the original function.
This allows intercepting PI API calls for introspection while
still allowing original function take care of handles. Or add
some post processing of the returned values.