Little refactoring of OrdVector #252

Job	Run time
run-test-performance (ubuntu-latest)	6m 52s
run-test-performance (macos-latest)	7m 39s
run-test-performance-base (ubuntu-latest)	7m 20s
run-test-performance-base (macos-latest)	7m 48s
run-tests (ubuntu-latest)	3m 5s
run-tests (macos-latest)	4m 27s
warnings-new (ubuntu-latest)	3m 49s
warnings-new (macos-latest)	4m 40s
warnings-base (ubuntu-latest)	3m 16s
warnings-base (macos-latest)	4m 22s
compare-versions (ubuntu-latest)	8s
compare-versions (macos-latest)	7s
code-coverage	2m 45s
compare-performance (ubuntu-latest)	21s
compare-performance (macos-latest)	1m 9s
	57m 48s

Provide feedback