ARROW-4951: [C++] Turn off cpp benchmarks in cpp docker images

[kszucs]

No description provided.

[codecov-io]

Codecov Report

Merging #3987 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #3987      +/-   ##
==========================================
- Coverage   87.82%   87.82%   -0.01%     
==========================================
  Files         732      732              
  Lines       90147    90147              
  Branches     1252     1252              
==========================================
- Hits        79176    79169       -7     
- Misses      10854    10857       +3     
- Partials      117      121       +4

Impacted Files	Coverage Δ
go/arrow/math/int64_avx2_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/memory/memory_avx2_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/math/float64_avx2_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/math/uint64_avx2_amd64.go	0% <0%> (-100%)	⬇️
go/arrow/memory/memory_amd64.go	28.57% <0%> (-14.29%)	⬇️
go/arrow/math/math_amd64.go	31.57% <0%> (-5.27%)	⬇️
go/arrow/math/float64_amd64.go	33.33% <0%> (ø)	⬆️
go/arrow/math/int64_amd64.go	33.33% <0%> (ø)	⬆️
go/arrow/math/uint64_amd64.go	33.33% <0%> (ø)	⬆️
cpp/src/plasma/thirdparty/ae/ae.c	71.69% <0%> (+0.94%)	⬆️
... and 5 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 37f898f...ed1fa0c. Read the comment docs.

[fsaintjacques]

May I ask why? They act as another compilation test. You can avoid running them by invoking ctest -L unittest.

[kszucs]

Oops, that was changed recently to ninja test.
Good hint to test the compilation itself, updating it. Thanks!

[kszucs]

+1, ci error is unrelated

[fsaintjacques]

+1