Cleanup `MaskFnAttentionBias.target_positions`. (#895) #21

	name: build-and-test
	on: [pull_request, push, merge_group]

	jobs:
	build-and-test-job:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	test-group: [a, b, c, d, e]
	steps:
	- uses: actions/checkout@v4
	- uses: docker/setup-buildx-action@v3
	- name: Gather test files
	run: find axlearn -name '*_test.py' > pytest_files.txt
	- name: Split test files into groups
	# GNU split lets us do "-n r/5" to round robin into 5 files without breaking lines
	# BSD split requires knowing the number of lines and uses "-l XX"
	run: split -n r/5 -a 1 pytest_files.txt split_pytest_files
	- name: Select a test group
	run: tr '\n' ' ' < split_pytest_files${{ matrix.test-group }} > test_files_oneline
	- name: Read test inputs
	id: test-selector
	run: echo "PYTEST_FILES='$(cat test_files_oneline)'" >> "$GITHUB_OUTPUT"
	- name: Run tests
	uses: docker/build-push-action@v6
	with:
	push: false
	target: ci
	context: .
	build-args: \|
	SKIP_PRECOMMIT=--skip-pre-commit
	PYTEST_FILES=${{ steps.test-selector.outputs.PYTEST_FILES }}

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