trace2: emit cmd_ancestry data for Windows

trace2: emit cmd_ancestry data for Windows

Since 2f732bf15e (tr2: log parent process name, 2021-07-21) it is now
now possible to emit a specific process ancestry event in TRACE2. We
should emit the Windows process ancestry data with the correct event
type.

To not break existing consumers of the data_json "windows/ancestry"
event, we continue to emit the ancestry data as a JSON event.

Signed-off-by: Matthew John Cheetham <mjcheetham@outlook.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>