[C++] Test failure in arrow-compute-aggregate-test

While building for Arch Linux, I’m observing 4 tests failures in the aforementioned suite:
```
[ RUN ] TestRandomInt64QuantileKernel.Overlapped
/build/arrow/src/apache-arrow-7.0.0/cpp/src/arrow/compute/kernels/aggregate_test.cc:3234: Failure
Value of: (quantiles[j] == numeric_scalar->value) || (std::isnan(quantiles[j]) && std::isnan(numeric_scalar->value))
Actual: false
Expected: true
[ FAILED ] TestRandomInt64QuantileKernel.Overlapped (6 ms)
```
```
[ RUN ] TestRandomInt64QuantileKernel.Sliced
/build/arrow/src/apache-arrow-7.0.0/cpp/src/arrow/compute/kernels/aggregate_test.cc:3234: Failure
Value of: (quantiles[j] == numeric_scalar->value) || (std::isnan(quantiles[j]) && std::isnan(numeric_scalar->value))
Actual: false
Expected: true
[ FAILED ] TestRandomInt64QuantileKernel.Sliced (25 ms)
```
```
[ RUN ] TestRandomFloatQuantileKernel.Exact
/build/arrow/src/apache-arrow-7.0.0/cpp/src/arrow/compute/kernels/aggregate_test.cc:3234: Failure
Value of: (quantiles[j] == numeric_scalar->value) || (std::isnan(quantiles[j]) && std::isnan(numeric_scalar->value))
Actual: false
Expected: true
[ FAILED ] TestRandomFloatQuantileKernel.Exact (0 ms)
```
```
[ RUN ] TestRandomFloatQuantileKernel.Sliced
/build/arrow/src/apache-arrow-7.0.0/cpp/src/arrow/compute/kernels/aggregate_test.cc:3234: Failure
Value of: (quantiles[j] == numeric_scalar->value) || (std::isnan(quantiles[j]) && std::isnan(numeric_scalar->value))
Actual: false
Expected: true
/build/arrow/src/apache-arrow-7.0.0/cpp/src/arrow/compute/kernels/aggregate_test.cc:3234: Failure
Value of: (quantiles[j] == numeric_scalar->value) || (std::isnan(quantiles[j]) && std::isnan(numeric_scalar->value))
Actual: false
Expected: true
/build/arrow/src/apache-arrow-7.0.0/cpp/src/arrow/compute/kernels/aggregate_test.cc:3234: Failure
Value of: (quantiles[j] == numeric_scalar->value) || (std::isnan(quantiles[j]) && std::isnan(numeric_scalar->value))
Actual: false
Expected: true
/build/arrow/src/apache-arrow-7.0.0/cpp/src/arrow/compute/kernels/aggregate_test.cc:3234: Failure
Value of: (quantiles[j] == numeric_scalar->value) || (std::isnan(quantiles[j]) && std::isnan(numeric_scalar->value))
Actual: false
Expected: true
[ FAILED ] TestRandomFloatQuantileKernel.Sliced (0 ms)
```
They are also happening with 6.0.1, but were not sometime ago so I suspect an update in some of arrow dependencies to be responsible for this. I’m happy to provide any information that could be useful, but I don’t want to create an account on JIRA, I try to limit the number of accounts I have everywhere.

Start at cpp/src/arrow/compute/kernels/aggregate_test.cc:3234 and the four failing quantile tests: TestRandomInt64QuantileKernel.Overlapped, TestRandomInt64QuantileKernel.Sliced, TestRandomFloatQuantileKernel.Exact, and TestRandomFloatQuantileKernel.Sliced. Reproduce the failures on Arch Linux and compare the Arrow dependency versions with a previously passing setup. Done means the affected tests pass consistently on the supported dependency versions.

Written by the indexing model from the issue text.