Adds the instruction count to the buffer header for drcachesim filtered traces, instead of just at thread exit, to aid in correlating filtered and unfiltered traces.
Updates the documentation and the trace_invariants test.
Augments the view tool to print out these markers. Further verified manually on a larger trace with the view tool:
<marker: filetype 65>
<marker: cache line size 64>
<marker: timestamp 13268850698443940>
<marker: tid 2539348 on core 1>
<marker: instruction count 33326>
0x00007f6f64314090 48 89 e7 mov %rsp, %rdi
0x00007f6f6432dce0 b8 0c 00 00 00 mov $0x0000000c, %eax
<marker: timestamp 13268850698727951>
<marker: tid 2539348 on core 1>
<marker: instruction count 40130>
0x00007f6f6432c906 c7 44 24 3c 00 00 00 movl $0x00000000, 0x3c(%rsp)
<...>
0x00007f6f63cc3670 4c 8b 05 f9 27 0f 00 mov <rel> 0x00007f6f63db5e70, %r8
<marker: timestamp 13268850699555438>
<marker: tid 2539348 on core 1>
<marker: instruction count 126115>Fixes #4857 (closed)