Adds a new drbbdup mode to drmemtrace which performs zero instrumentation (except drwrap cleanup). This mode is used when attaching for the period prior to full control of all threads and when detaching prior to starting to let threads go native, to avoid uneven thread instrumentation during these incremental staggered processes. The mode is initially under an off-by-default new option -align_endpoints while drbbdup stability is being worked on (i#5686).
Threads that did nothing during the trace-mode period are now omitted from the trace.
Adds a test by adding 4 idle threads to burst_threads and ensuring they do not show up in the trace.
Alignment itself was tested manually by running larger applications and analyzing the timestamp ranges in the trace.
Fixes the burst_replace test to work properly with .zip output (the output regex still matched despite a printed error from raw2trace, it seems).
Timestamps during detach require further work as they inaccurately imply executing after tracing mode was turned off. The next part will address this issue.
Issue: #2039 (closed), #5686