the last matched 'V' blcok in trace frame.
gdb/gdbserver:
* tracepoint.c (traceframe_read_tsv): Look for the last matched
'V' block in trace frame.
gdb/testsuite:
* gdb.trace/tsv.exp (check_tsv): New.
(top level): Save a tfile on current trace session. Call
check_tsv on live target. Load the tfile with target tfile
and call check_tsv again.