Improved formatter.py performance #1297

Job	Run time
Setup cache and determine changed repositories (3.7)	10m 39s
Lint Python scripts (3.7)	17s
Check file sizes	8s
Lint tool-list (3.7)	1m 28s
Lint R scripts (ubuntu-20.04, release)	1m 25s
Test tools (0, 3.7)	8m 13s
Test tools (1, 3.7)	5m 10s
Test tools (2, 3.7)	8m 18s
Test tools (3, 3.7)	6m 37s
Combine chunked test results (3.7)	50s
Check workflow success	3s
Deploy	0s
Report deploy status	0s
	43m 8s

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