Changes test_func_order tests for some unary functions

[oleksandr-pavlyk]

The change is to iterate over permutations first, doing some work that does not depend on the order, and then iterate over orders.

This should save doing some computations 4 times (once for each order), now only done once.

The change shaves 4 seconds off of execution of entire test suite on CPU device (from 5 minutes 6 seconds to 5 minutes and 2 seconds).

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[github-actions]

Deleted rendered PR docs from intelpython.github.com/dpctl, latest should be updated shortly. 🤞

[coveralls]

coverage: 87.892%. remained the same
when pulling cda4574 on optimize_tests_order
into 6ae9f3d on master.

[github-actions]

Array API standard conformance tests for dpctl=0.17.0dev0=py310h15de555_318 ran successfully.
Passed: 870
Failed: 8
Skipped: 92

[ndgrigorian]

LGTM!