windows: Add thread ID in SuspendThread error warning message.

windows: Add thread ID in SuspendThread error warning message.

This patch adds the thread ID to a warning printed when a call to
SuspendThread fails. It will help investigate issues, particularly
when correlated with the various debug traces provided by the
windows-nat module.

For the record, the output has been changed from...

    warning: SuspendThread failed. (winerr 6)

... to ...

    warning: SuspendThread (tid=0x720) failed. (winerr 6)

gdb/ChangeLog:

        * window-nat.c (thread_rec): Add thread ID in SuspendThread
        warning message.