Move diff-range computation into utils #10719

Job	Run time
analyze-other (python)	56s
analyze-other (actions)	53s
check-codeql-versions	32s
analyze-javascript (ubuntu-22.04)	4m 13s
analyze-javascript (ubuntu-22.04, linked)	4m 20s
analyze-javascript (ubuntu-24.04, linked)	4m 16s
analyze-javascript (windows-2022)	5m 22s
analyze-javascript (ubuntu-24.04)	4m 20s
analyze-javascript (macos-13)	9m 27s
analyze-javascript (macos-14)	5m 26s
analyze-javascript (macos-15, linked)	4m 33s
analyze-javascript (macos-15)	8m 48s
analyze-javascript (windows-2025)	5m 32s
analyze-javascript (windows-2022, linked)	5m 17s
analyze-javascript (macos-14, linked)	5m 59s
analyze-javascript (windows-2025, linked)	9m 15s
analyze-javascript (macos-13, linked)	11m 5s
	1h 30m 14s

Provide feedback