Multi-window traces contain low activity at the beginning of a new window

[bete0]

Our internal tools discovered a case when creating multi-window traces, there are missing instructions in a new buffer in the new window:

     1	instrs      6952, segments      1, threads     1
     2	instrs         0, segments      0, threads     0
     3	instrs         0, segments      0, threads     0
     4	instrs         0, segments      0, threads     0
     5	instrs         0, segments      0, threads     0
     6	instrs         0, segments      0, threads     0
     7	instrs         0, segments      0, threads     0
     8	instrs         0, segments      0, threads     0
     9	instrs         0, segments      0, threads     0
    10	instrs         0, segments      0, threads     0
    11	instrs         0, segments      0, threads     0
    12	instrs         0, segments      0, threads     0
    13	instrs         0, segments      0, threads     0
    14	instrs         0, segments      0, threads     0
    15	instrs         0, segments      0, threads     0
    <...>
   290	instrs         0, segments      0, threads     0
   291	instrs         0, segments      0, threads     0
   292	instrs         0, segments      0, threads     0
   293	instrs         0, segments      0, threads     0
   294	instrs         0, segments      0, threads     0
   295	instrs   1766865, segments    240, threads     1
   296	instrs  11316277, segments   1537, threads     1
   297	instrs  11348190, segments   1541, threads     1
   298	instrs  11342445, segments   1540, threads     1
   299	instrs  11324532, segments   1538, threads     1
   <...>
   996	instrs  16444436, segments   2037, threads     1
   997	instrs  15637905, segments   1956, threads     1
   998	instrs  16135216, segments   2003, threads     1
   999	instrs  16327844, segments   2017, threads     1
  1000	instrs  14145335, segments   1825, threads     1

This was caused by a timestamp from the end of the prior window was not updated and being used in the first buffer in the new window.