[GUI.Batch] Remove duplicated speed result

[fredroy]

Running batch mode was always displaying the (same) result twice at the end (and bothersome to grep everytime 😶‍🌫️)

This PR itself just removes one line (one using getFastTime() )

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For a future PR maybe.

After investigation (and some explanation from Mister C.) , it seems it was supposed to trace with different time measurement. In a nutshell, it depends if SOFA_RDTSC is defined. If defined getFastTime() will use a CPU instruction (rdtsc) instead of syscall, which involves overhead apparently.

The problem is:

• nowhere SOFA_RDTSC can be enabled (no CMake option) so you have to add manually the define in CXX_FLAGS. otherwise getFastTime = getRefTime() )
• it needs to be used with computeTicksPerSec() which is not reliable with today's CPU (changes with cpu frequency, turboboost, etc) and multi-CPU (multicore, bigLITTLE, etc)
• and arm does not support it anyway

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I have read, understand, and agree SOFA Developer Certificate of Origin (DCO).

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Reviewers will merge this pull-request only if

• it builds with SUCCESS for all platforms on the CI.
• it does not generate new warnings.
• it does not generate new unit test failures.
• it does not generate new scene test failures.
• it does not break API compatibility.
• it is more than 1 week old (or has fast-merge label).