Fix sort for size 1 axes

[ndgrigorian]

Some sorting algorithms used (in particular radix_sort) assert that elements to be sorted must be greater than 1, and this can cause failures in debug builds, like coverage

This PR proposes a fix: copy in sort and memset to 0 in argsort when sort_nelems is 1

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[github-actions]

View rendered docs @ https://intelpython.github.io/dpctl/pulls/2106/index.html

[github-actions]

Array API standard conformance tests for dpctl=0.21.0dev0=py310h93fe807_16 ran successfully.
Passed: 1114
Failed: 7
Skipped: 119

[coveralls]

coverage: 84.984% (-0.005%) from 84.989%
when pulling 1838afa on fix-sorting-size-1-axes
into 35a8c26 on master.

[github-actions]

Array API standard conformance tests for dpctl=0.21.0dev0=py310h93fe807_21 ran successfully.
Passed: 1115
Failed: 6
Skipped: 119

[antonwolfy]

Thank you @ndgrigorian for catching and resolving that