[C++] Multiple test failures on PowerPC (big endian), on 15.0.2

[mgorny]

Describe the bug, including details regarding any error messages, version, and platform.

When running the test suite on Gentoo PowerPC (POWER9), I'm getting the following test failures:

The following tests FAILED:
         18 - arrow-compute-internals-test (Failed)
         25 - arrow-utility-test (Failed)
         40 - parquet-internals-test (Failed)
         41 - parquet-reader-test (Failed)
         43 - parquet-arrow-test (Failed)
         44 - parquet-arrow-internals-test (Failed)
         45 - parquet-encryption-test (Failed)
         46 - parquet-encryption-key-management-test (Failed)
Errors while running CTest

Build log: build.txt
Test log: test.txt

Some of them clearly look like endianness issues, others are unclear to me.

Component(s)

C++

[QuLogic]

25 - arrow-utility-test (Failed)

Should be fixed by #44768.

Some of the others should be (partially?) fixed by #44787.

[mgorny]

25 - arrow-utility-test (Failed)

Should be fixed by #44768.

Indeed it seems to be.

Some of the others should be (partially?) fixed by #44787.

Yeah, looks like there are fewer failures (but still most of them fail).