target, record: add PTID argument to to_record_is_replaying
The to_record_is_replaying target method is used to query record targets if
they are replaying. This is currently interpreted as "is any thread being
replayed".
Add a PTID argument and change the interpretation to "is any thread matching
PTID being replayed".
Change all users to pass minus_one_ptid to preserve the old meaning.
The record full target does not really support multi-threading and ignores
the PTID argument.