DAOS-16585 tests: Fix NLT handling of __fxstat detection #6799

Job	Run time
Build DAOS (alma.8)	38m 24s
Build DAOS (ARM64) (ubuntu, clang)	1s
Build DAOS (ARM64) (alma.8, clang)	1s
Create Docker images (ubuntu)	9m 8s
Build DAOS (alma.9)	38m 30s
Build DAOS (ARM64) (leap.15, clang)	1s
Create Docker images (rocky)	9m 19s
Build DAOS (rocky.8)	40m 51s
Create Docker images (fedora)	10m 2s
Build DAOS (ubuntu)	35m 10s
Create Docker images (leap.15)	11m 18s
Run DAOS/NLT tests (ubuntu)	24m 42s
Build DAOS in image (ubuntu, clang)	23m 22s
Build DAOS in image (ubuntu, gcc)	23m 21s
Build DAOS in image (rocky, clang)	22m 44s
Build DAOS in image (rocky, gcc)	35m 19s
Build DAOS in image (fedora, clang)	23m 59s
Build DAOS in image (fedora, gcc)	26m 6s
Build DAOS in image (leap.15, clang)	24m 48s
Build DAOS in image (leap.15, gcc)	24m 30s
	7h 1m 36s

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