gtest fails on macos-latest: `X == X_UNC` or `X == X_ALT`

[zaikunzhang]

https://github.com/s-prima/prima/actions/runs/21637931483

export TESTDIM=small && export TESTSEED=2606 && export FFLAGS=-O3 && make clean && make gtest_i2_r8_d1_tst.cobyla # trigssqs
export TESTDIM=small && export TESTSEED=2606 && export FFLAGS=-O3 && make clean && make gtest_i2_r8_d1_tst.lincoa # chebquad
export TESTDIM=small && export TESTSEED=2606 && export FFLAGS=-O3 && make clean && make gtest_i2_r8_d1_tst.bobyqa # chebquad

Reproducible on local machine zMS.

Try also gtest_i2_r4_d1_tst.bobyqa and gtest_i2_r8_d1_tst.lincoa, which also failed.

[zaikunzhang]

N.B.: The failure seems random: it happens every few tests, but not all.

[zaikunzhang]

Commit hash: 7da893d

[zaikunzhang]

See this run:

https://github.com/s-prima/prima/actions/runs/22023414613

Rerun it to reproduce the failures.