CHORE: Factored out _broadcast_shape implementation

[oleksandr-pavlyk]

The implementation takes an iterable of shapes. This is useful for implementation of general broadcasting function.

Otherwise, no functional change.

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[github-actions]

View rendered docs @ https://intelpython.github.io/dpctl/pulls/1047/index.html

[coveralls]

Coverage: 82.081% (+0.005%) from 82.076% when pulling f9413c5 on chore-factor-out-broadcast_impl into 949711e on master.

[coveralls]

Coverage: ?%. Remained the same when pulling f9413c5 on chore-factor-out-broadcast_impl into 949711e on master.

[github-actions]

Array API standard conformance tests for dpctl=0.14.1dev1=py310h76be34b_47 ran successfully.
Passed: 33
Failed: 801
Skipped: 280

[github-actions]

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

[github-actions]

Array API standard conformance tests for dpctl=0.14.1dev1=py310h76be34b_47 ran successfully.
Passed: 33
Failed: 801
Skipped: 280