We record submission time for commands submitted via handler, but this was missing for shortcut commands.

Also this PR changes the values returned by command_submit, command_start, command_end for non-host events without UR event handle - such events may appear if command is nop, for example, USM operations for 0 bytes.
Such scenario is not explicitly specified in SYCL spec. Before changes, we used to return 0 for all three quieries. But for consistency,I believe it makes sense to return the same recorded submit time for all three: command_submit = command_start = command_end. It seems more convenient from user's perspective, for example if user submits sequence set of commands and there is some nop command in the middle of sequence:
command1
command2 (nop)
command3
and user calculates wants to calculate differences between submission time (or start time) of command2 and command1, then he will get negative value: 0 - submit_time_of_command2 (if we return 0).
And there can be more nop operations (if SYCL runtime optimizes out something), so if we return 0, user always has to check if the returned timestamp is 0 or not before using it in any calculations. So returning non-zero submit time seems better.