Remove duplicate call to find cmake build dir in scripts/gen_coverage.py

[antonwolfy]

This PR removes leftover from #2172, which added duplicating call to find CMake build directory in scripts/gen_coverage.py script.

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[github-actions]

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

[coveralls]

coverage: 86.245%. remained the same
when pulling 8cd29dd on remove-excess-find-call-in-gen_coverage.py
into 4c57ee7 on master.

[github-actions]

Array API standard conformance tests for dpctl=0.22.0dev0=py310h93fe807_104 ran successfully.
Passed: 1115
Failed: 43
Skipped: 82