[trans-mem] Move state from gtm_thread to gtm_transaction

[Torvald Riegel <triegel at redhat dot com>]

patch3:
After the previous change to flat nesting by default, checkpoints, and
thus having only a single gtm_transaction object per thread, we can move
the local_tid field to gtm_transaction too. As a result, we don't have
to access gtm_thread in GTM_begin_transaction anymore.

patch4:
A small fix that adds a missing set-up call for gtm_thread. And a
matching test case, which tests that the functions in query.cc work even
if no transaction has been executed so far in this thread.

OK for branch?

Attachment: patch3
Description: Text document

Attachment: patch4
Description: Text document