unit: add UMTensor expression tests #1398

Job	Run time
ubuntu-24.04: /usr/bin/g++-14 Debug Pthreads	9m 7s
ubuntu-24.04: /usr/bin/g++-14 Debug PaRSEC	8m 23s
ubuntu-24.04: /usr/bin/g++-14 Release Pthreads	6m 31s
macos-latest: clang++ Release PaRSEC	4m 34s
macos-latest: clang++ Debug PaRSEC	18m 31s
macos-latest: clang++ Release Pthreads	12m 55s
macos-latest: clang++ Debug Pthreads	14m 51s
ubuntu-24.04: /usr/bin/g++-14 Release PaRSEC	5m 57s
	1h 20m 49s

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