utils: add fio benchmarks

[mramotowski]

Add fio benchmarks for pmemfile performance tests

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This change is 

[codecov[bot]]

Codecov Report

Merging #378 into master will increase coverage by 0.03%. The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #378      +/-   ##
==========================================
+ Coverage   77.01%   77.04%   +0.03%     
==========================================
  Files          67       67              
  Lines        8261     8261              
  Branches     1658     1658              
==========================================
+ Hits         6362     6365       +3     
+ Misses       1486     1484       -2     
+ Partials      413      412       -1

Flag	Coverage Δ
#ltp_tests	46.54% <ø> (-0.04%)	:arrow_down:
#sqlite_tests	45.25% <ø> (ø)	:arrow_up:
#tests_antool	14.72% <ø> (ø)	:arrow_up:
#tests_posix_multi_threaded	25.11% <ø> (+0.06%)	:arrow_up:
#tests_posix_single_threaded	54.28% <ø> (-0.03%)	:arrow_down:
#tests_preload	44.77% <ø> (-0.05%)	:arrow_down:

Impacted Files	Coverage Δ
src/libpmemfile-posix/data.c	94.42% <0%> (-0.4%)	:arrow_down:
src/libpmemfile-posix/dir.c	85.99% <0%> (+0.98%)	:arrow_up:

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[krzycz]

Reviewed 21 of 21 files at r1. Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[sarahjelinek]

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Reviewed 21 of 21 files at r1. Review status: :shipit: all files reviewed at latest revision, all discussions resolved, all commit checks successful.

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Comments from Reviewable